Light field device, pixel rendering method therefor, and adjusted vision perception system and method using same

ABSTRACT

Described are various embodiments of a light field device, pixel rendering method therefor, and vision perception system and method using same. One embodiment describes a method to adjust user perception of an image portion to be rendered via a set of pixels and a corresponding array of light field shaping elements (LFSE), the method comprising: projecting an adjusted image ray trace between a given pixel and a user pupil location to intersect an adjusted image location for a given perceived image depth given a direction of a light field emanated by the given pixel based on a given LFSE intersected thereby; upon the adjusted image ray trace intersecting a given image portion associated with the given perceived image depth, associating with the given pixel an adjusted image portion value designated for the adjusted image location based on the intersection; and rendering for each given pixel the adjusted image portion value associated therewith.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.17/302,392 filed April 30, 2021, which is a continuation-in-part of U.S.patent application Ser. No. 17/309,133 filed April 28, 2021, which is aUS national stage of International Application No. PCT/IB2020/057887filed Aug. 22, 2020, which claims priority to, and is a continuation of,U.S. patent application Ser. No. 16/810,143 filed Mar. 5, 2020 andissued as U.S. Pat. No. 10,761,604 on Sep. 1, 2020, which is acontinuation-in-part of U.S. patent application Ser. No. 16/569,137filed Sep. 12, 2019 and issued as U.S. Pat. No. 10,642,355 on May 5,2020, which is a continuation of U.S. patent application Ser. No.16/510,673 filed Jul. 12, 2019 and issued as U.S. Pat. No. 10,474,235 onNov. 12, 2019, which is a continuation of U.S. patent application Ser.No. 16/259,845 filed Jan. 28, 2019 and issued as U.S. Pat. No.10,394,322 on Aug. 27, 2020, which claims priority to Canadian PatentApplication No. 3,021,636 filed Oct. 22, 2018, the entire disclosure ofeach of which is hereby incorporated herein by reference. InternationalApplication No. PCT/IB2020/057887 is a continuation-in-part ofInternational Application No. PCT/IB2019/058955 filed Oct. 21, 2019, theentire disclosure of each of which is also hereby incorporated herein byreference. International Application No. PCT/IB2020/057887 also claimspriority to U.S. Provisional Application No. 62/929,639 filed Nov. 1,2019, the entire disclosure of which is also hereby incorporated hereinby reference. U.S. patent application Ser. No. 16/810,143 is also acontinuation-in-part of U.S. patent application Ser. No. 16/551,572filed Aug. 26, 2019 and issued as U.S. Pat. No. 10,636,116 on Apr. 28,2020, and a continuation-in-part of International Application No.PCT/IB2019/058955 filed Oct. 21, 2019, the entire disclosure of each ofwhich is also hereby incorporated herein by reference.

U.S. patent application Ser. No. 17/302,392 is also acontinuation-in-part of International Application No. PCT/US2020/058392filed Oct. 30, 2020, which is a continuation-in-part of U.S. patentapplication Ser. No. 16/810,143 filed Mar. 5, 2020 and issued as U.S.Pat. No. 10,761,604 on Sep. 1, 2020, the entire disclosure of which ishereby incorporated by reference. PCT/US2020/058392 also claims priorityto U.S. Provisional Application No. 62/929,639 filed Nov. 1, 2019 andInternational Application Serial No. PCT/IB2020/057887 filed Aug. 22,2020, the entire disclosure of each of which is hereby incorporatedherein by reference.

FIELD OF THE DISCLOSURE

The present disclosure relates to digital displays, and in particular,to a light field device, multi-depth pixel rendering method therefor,and multi-depth vision perception system and method using same.

BACKGROUND

Light field displays are known to adjust a user's perception of an inputimage by adjusting a light field emanated by the display so to controlhow a light field image is ultimately projected for viewing. Forinstance, in some examples, users who would otherwise require correctiveeyewear such as glasses or contact lenses, or again bifocals, mayconsume images produced by such devices in clear or improved focuswithout the use of such eyewear. Other light field display applications,such as 3D displays, are also known.

This background information is provided to reveal information believedby the applicant to be of possible relevance. No admission isnecessarily intended, nor should be construed, that any of the precedinginformation constitutes prior art.

SUMMARY

The following presents a simplified summary of the general inventiveconcept(s) described herein to provide a basic understanding of someaspects of the disclosure. This summary is not an extensive overview ofthe disclosure. It is not intended to restrict key or critical elementsof the embodiments of the disclosure or to delineate their scope beyondthat which is explicitly or implicitly described by the followingdescription and claims.

A need exists for a light field display, adjusted pixel rendering methodtherefor, and adjusted vision perception system and method using same,that overcome some of the drawbacks of known techniques, or at least,provide a useful alternative thereto. Some aspects of disclosure provideembodiments of such systems, methods, and displays.

In accordance with one aspect, there is provided a computer-implementedmethod, automatically implemented by one or more digital processors, toadjust user perception of an image portion to be rendered via a set ofpixels and a corresponding array of light field shaping elements (LFSE),the method comprising, for each given pixel of at least some of the setof pixels, digitally: projecting an adjusted image ray trace betweensaid given pixel and a user pupil location to intersect an adjustedimage location for a given perceived image depth given a direction of alight field emanated by said given pixel based on a given LFSEintersected thereby; upon said adjusted image ray trace intersecting agiven image portion associated with said given perceived image depth,associating with said given pixel an adjusted image portion valuedesignated for said adjusted image location based on said intersection;and rendering for each said given pixel said adjusted image portionvalue associated therewith, thereby perceptively rendering said adjustedimage portion at said perceived image depth.

In one embodiment, the method is to adjust perception of distinct imageportions, and further comprises, upon said adjusted image ray tracefailing to intersect said given image portion associated with said givenperceived image depth, repeating said projecting and associating for asubsequent perceived image depth and adjusted image portion associatedtherewith, thereby rendering distinctly perceptively adjusted imageportions perceptively rendered at respectively corresponding perceivedimage depths.

In accordance with another aspect, there is provided a device operableto dynamically adjust user perception of an input image, the devicecomprising: an array of digital display pixels; a corresponding array oflight field shaping elements (LFSEs) shaping a light field emanatingfrom said pixels; and a hardware processor operable on pixel data forthe input image to output adjusted image pixel data to be rendered viasaid LFSEs to dynamically adjust user perception of the input image asrendered therethrough by: digitally mapping the input image on anadjusted image plane corresponding to a designated vision correctionparameter associated with a given visual acuity level; for each givenpixel, digitally: projecting an adjusted image ray trace between saidgiven pixel and a user pupil location to intersect said adjusted imageplane at a given adjusted image location given a direction of a lightfield emanated by said given pixel based on a given LFESE intersectedthereby; and associating an adjusted image pixel value designated forsaid given adjusted image location with said given pixel based on saidmapping; rendering each said given pixel according to said adjustedpixel value, thereby rendering a perceptively adjusted version of theinput image that at least partially accommodates said given visualacuity level; and adjusting said designated vision correction parameterto accommodate for a distinct visual acuity level until an optimalvisual acuity level is identified.

In one embodiment, the input image is an optotype, and wherein saidoptimal visual acuity level is associated with a visual acuity of theuser in prescribing corrective eyewear or surgery.

In one embodiment, the given visual acuity level corresponds with aminimum reading distance or a maximum reading distance.

In one embodiment, the device further comprises an adjustable refractiveoptical system, interposed between said array of pixels and said userpupil location so to set a selectable coarse refractive correction andthus further refract and thus redirect said light field emanated by eachsaid given pixel, wherein said adjusted image ray trace is furtherprojected between said given pixel and said user pupil location tointersect said adjusted image plane at said given adjusted imagelocation based on said given LFSE and a current coarse refractivecorrection of said adjustable refractive optical system, wherein saidoptimal visual acuity level is identified as a function of saiddesignated vision correction parameter and said current coarserefractive correction.

In one embodiment, the adjustable refractive optical system comprises atleast one of a tunable lens or a lens selectable from an array ofselectable lenses.

In one embodiment, the device is operable to dynamically adjust userperception of distinct image portions by: digitally processing eachgiven image portion to be perceptively rendered according to distinctvision correction parameters to accommodate for distinct visual acuitylevels for comparative purposes; and adjusting said distinct visioncorrection parameters until said optimal visual acuity level isidentified.

In one embodiment, the distinct visual acuity levels correspond withdistinct comfortable viewing distances and each given image portion ismapped to a respective adjusted image plane accordingly; said adjustedimage ray trace is projected to identify a corresponding adjusted imagelocation for a first viewing distance; upon said adjusted image raytrace intersecting said given image portion associated with said firstviewing distance, associating with said given pixel an adjusted imageportion value designated for said corresponding adjusted image locationbased on said intersection; otherwise repeating said projecting andassociating for a subsequent viewing distance; and rendering for eachsaid given pixel said adjusted image portion value associated therewith,thereby rendering distinctly perceptively adjusted image portions.

In one embodiment, the distinct image portions comprise distinctoptotypes or distinct levels of correction for a same optotype.

In one embodiment, the distinct image portions comprise two side-by-sideimage portions.

In one embodiment, the distinct image portions comprise an array or gridof image portions.

In one embodiment, the device further comprises an adjustable refractiveoptical system interposed between said array of pixels and said userpupil location so to set a selectable common coarse refractivecorrection and thus further refract and thus redirect said light fieldemanated by each said given pixel, wherein the device is furtheroperable to digitally process each said given image portion to beperceptively rendered according to said distinct vision correctionparameters based on a current common coarse refractive correction.

In one embodiment, the device is a refractor or phoropter.

In one embodiment, the device further comprises a user eye alignmentstructure or a pupil tracking device to define said user pupil location.

In one embodiment, the device further comprises an optical reflector tofold an optical path between said user pupil location and said array ofdigital display pixels.

In one embodiment, the adjusted image plane comprises one of a virtualimage plane virtually positioned relative to the digital display tocorrespond with said given visual acuity level or a user retinal planebased on a user eye focus parameter corresponding with said given visualacuity level.

In accordance with another aspect, there is provided a subjective eyetest device comprising: an array of digital display pixels; acorresponding array of light field shaping elements (LFSEs) shaping alight field emanating from said pixels; and a hardware processoroperable on pixel data for a defined optotype to output adjusted imagepixel data to be rendered via said LFSEs to dynamically adjust userperception of said defined optotype as rendered therethrough by:digitally mapping said defined optotype on an adjusted image planecorresponding to a designated vision correction parameter associatedwith a given visual acuity level; for each given pixel, digitally:projecting an adjusted image ray trace between said given pixel and auser pupil location to intersect said adjusted image plane at a givenadjusted image location given a direction of a light field emanated bysaid given pixel based on a given LFESE intersected thereby; andassociating an adjusted image pixel value designated for said givenadjusted image location with said given pixel based on said mapping; andrendering each said given pixel according to said adjusted pixel value,thereby rendering a perceptively adjusted version of said definedoptotype that at least partially accommodates said given visual acuitylevel; and adjusting said designated vision correction parameter toaccommodate for a distinct visual acuity level until an optimal visualacuity level is identified.

In one embodiment, the computer-implemented method, automaticallyimplemented by one or more digital processors, to dynamically adjustuser perception of an input image to be rendered by an array of digitaldisplay pixels via a corresponding array of light field shaping elements(LFSE), the method comprising: digitally mapping the input image on anadjusted image plane corresponding to a designated vision correctionparameter associated with a given visual acuity level; for each givenpixel, digitally: projecting an adjusted image ray trace between saidgiven pixel and a user pupil location to intersect said adjusted imageplane at a given adjusted image location given a direction of a lightfield emanated by said given pixel based on a given LFESE intersectedthereby; and associating an adjusted image pixel value designated forsaid given adjusted image location with said given pixel based on saidmapping; rendering each said given pixel according to said adjustedpixel value, thereby rendering a perceptively adjusted version of theinput image that at least partially accommodates said given visualacuity level; and adjusting said designated vision correction parameterto accommodate for a distinct visual acuity level until an optimalvisual acuity level is identified.

In one embodiment, the method dynamically adjusts user perception ofdistinct image portions by: digitally processing each given imageportion to be perceptively rendered according to distinct visioncorrection parameters to accommodate for distinct visual acuity levelsfor comparative purposes; and adjusting said distinct vision correctionparameters until said optimal visual acuity level is identified.

In one embodiment, the distinct visual acuity levels correspond withdistinct comfortable viewing distances and each given image portion ismapped to a respective adjusted image plane accordingly; said adjustedimage ray trace is projected to identify a corresponding adjusted imagelocation for a first viewing distance; upon said adjusted image raytrace intersecting said given image portion associated with said firstviewing distance, associating with said given pixel an adjusted imageportion value designated for said corresponding adjusted image locationbased on said intersection; otherwise repeating said projecting andassociating for a subsequent viewing distance; and rendering for eachsaid given pixel said adjusted image portion value associated therewith,thereby rendering distinctly perceptively adjusted image portions.

In one embodiment, the distinct image portions comprise distinctoptotypes or distinct levels of correction for a same optotype, andwherein said distinct image portions comprise side-by-side imageportions or an array or grid of image portions.

In one embodiment, the adjusted image plane comprises one of a virtualimage plane virtually positioned relative to the digital display tocorrespond with said given visual acuity level or a user retinal planebased on a user eye focus parameter corresponding with said given visualacuity level.

In one embodiment, the method further comprises, prior to saidprojecting: calculating a vector between said given pixel and said userpupil location; and approximating said direction of said light fieldemanated by said given pixel based on said given LFSE intersected bysaid vector.

In one embodiment, the method further comprises digitally accounting foran adjustable refractive optical system interposed between said array ofpixels and said user pupil location so to set a selectable coarserefractive correction and thus further refract and thus redirect saidlight field emanated by each said given pixel, wherein said adjustedimage ray trace is further projected between said given pixel and saiduser pupil location to intersect said adjusted image plane at said givenadjusted image location based on said given LFSE and a current coarserefractive correction of said adjustable refractive optical system,wherein said optimal visual acuity level is identified as a function ofsaid designated vision correction parameter and said current coarserefractive correction.

In accordance with another aspect, there is provided a non-transitorycomputer-readable medium comprising digital instructions to beimplemented by one or more digital processors to dynamically adjust userperception of an input image to be rendered by an array of digitaldisplay pixels via a corresponding array of light field shaping elements(LFSE), by: digitally mapping the input image on an adjusted image planecorresponding to a designated vision correction parameter associatedwith a given visual acuity level; for each given pixel, digitally:projecting an adjusted image ray trace between said given pixel and auser pupil location to intersect said adjusted image plane at a givenadjusted image location given a direction of a light field emanated bysaid given pixel based on a given LFESE intersected thereby; andassociating an adjusted image pixel value designated for said givenadjusted image location with said given pixel based on said mapping;rendering each said given pixel according to said adjusted pixel value,thereby rendering a perceptively adjusted version of the input imagethat at least partially accommodates said given visual acuity level; andadjusting said designated vision correction parameter to accommodate fora distinct visual acuity level until an optimal visual acuity level isidentified.

In one embodiment, the non-transitory computer-readable medium furthercomprises digital instructions to be implemented to dynamically adjustuser perception of distinct image portions by: digitally processing eachgiven image portion to be perceptively rendered according to distinctvision correction parameters to accommodate for distinct visual acuitylevels for comparative purposes; and adjusting said distinct visioncorrection parameters until said optimal visual acuity level isidentified.

In one embodiment, the distinct visual acuity levels correspond withdistinct comfortable viewing distances and each given image portion ismapped to a respective adjusted image plane accordingly; said adjustedimage ray trace is projected to identify a corresponding adjusted imagelocation for a first viewing distance; upon said adjusted image raytrace intersecting said given image portion associated with said firstviewing distance, associating with said given pixel an adjusted imageportion value designated for said corresponding adjusted image locationbased on said intersection; otherwise repeating said projecting andassociating for a subsequent viewing distance; and rendering for eachsaid given pixel said adjusted image portion value associated therewith,thereby rendering distinctly perceptively adjusted image portions.

In one embodiment, the distinct image portions comprise distinctoptotypes or distinct levels of correction for a same optotype, andwherein said distinct image portions comprise side-by-side imageportions or an array or grid of image portions.

In one embodiment, the adjusted image plane comprises one of a virtualimage plane virtually positioned relative to the digital display tocorrespond with said given visual acuity level or a user retinal planebased on a user eye focus parameter corresponding with said given visualacuity level.

In one embodiment, the non-transitory computer-readable furthercomprising instructions for, prior to said projecting: calculating avector between said given pixel and said user pupil location; andapproximating said direction of said light field emanated by said givenpixel based on said given LFSE intersected by said vector.

In one embodiment, the non-transitory computer-readable medium furthercomprising digital instructions to be implemented to account for anadjustable refractive optical system interposed between said array ofpixels and said user pupil location so to set a selectable coarserefractive correction and thus further refract and thus redirect saidlight field emanated by each said given pixel, wherein said adjustedimage ray trace is further projected between said given pixel and saiduser pupil location to intersect said adjusted image plane at said givenadjusted image location based on said given LFSE and a current coarserefractive correction of said adjustable refractive optical system,wherein said optimal visual acuity level is identified as a function ofsaid designated vision correction parameter and said current coarserefractive correction.

In accordance with another aspect, there is provided acomputer-implemented method, automatically implemented by one or moredigital processors, to automatically adjust user perception of distinctimage portions to be rendered on a digital display via a set of pixelsthereof, wherein the digital display has an array of light field shapingelements (LFSE), the method comprising: digitally processing each givenimage portion to be perceptively rendered at a corresponding perceivedimage depth by, for each given pixel in at least some of the pixels,digitally: calculating a vector between said given pixel and a userpupil location; approximating a direction of a light field emanated bysaid given pixel based on a given LFSE intersected by said vector;projecting an adjusted image ray trace between said given pixel and saidgiven LFSE to identify a corresponding adjusted image location for afirst perceived image depth given said direction; upon said adjustedimage ray trace intersecting said given image portion associated withsaid first perceived image depth, associating with said given pixel anadjusted image portion value designated for said corresponding adjustedimage location based on said intersection; otherwise repeating saidprojecting and associating for a subsequent perceived image depth; andrendering for each said given pixel said adjusted image portion valueassociated therewith, thereby rendering distinctly perceptively adjustedimage portions.

In one embodiment, each of said image portions is digitally mapped to acorresponding virtual image plane virtually positioned relative to thedigital display at said corresponding perceived image depth, and whereinsaid intersection is defined on said corresponding virtual image plane.

In one embodiment, each of said image portions is mapped to a userretinal plane in accordance with said corresponding perceived imagedepth based on a user eye focus parameter, and wherein said intersectionis defined on said retinal plane by redirecting said adjusted image raytrace at said pupil location in accordance with said user eye focusparameter.

In one embodiment, said projecting and associating are implemented inparallel for each said given pixel of at least a subset of said pixels.

In accordance with another aspect, there is provided a non-transitorycomputer-readable medium comprising digital instructions to beimplemented by one or more digital processors to automatically adjustuser perception of distinct image portions to be rendered on a digitaldisplay via a set of pixels thereof, wherein the digital display has anarray of light field shaping elements (LFSE), by: digitally processingeach given image portion to be perceptively rendered at a correspondingperceived image depth by, for each given pixel in at least some of thepixels, digitally: calculating a vector between said given pixel and auser pupil location; approximating a direction of a light field emanatedby said given pixel based on a given LFSE intersected by said vector;projecting an adjusted image ray trace between said given pixel and saidgiven LFSE to identify a corresponding adjusted image location for afirst perceived image depth given said direction; upon said adjustedimage ray trace intersecting said given image portion associated withsaid first perceived image depth, associating with said given pixel anadjusted image portion value designated for said corresponding adjustedimage location based on said intersection; otherwise repeating saidprojecting and associating for a subsequent perceived image depth; andrendering for each said given pixel said adjusted image portion valueassociated therewith, thereby rendering distinctly perceptively adjustedimage portions.

In accordance with another aspect, there is provided a digital displaydevice operable to automatically adjust user perception of distinctimage portions to be rendered thereon, the device comprising: a digitaldisplay medium comprising an array of pixels and operable to render apixelated image accordingly; an array of light field shaping elements(LFSEs) to shape a light field emanating from said pixels and thereby atleast partially govern a projection thereof from said display mediumtoward the user; and a hardware processor operable on pixel data for theinput image portions to output adjusted image pixel data to be renderedvia said LFSEs to adjust user perception of said input image portions asrendered therethrough by: digitally processing each given image portionto be perceptively rendered at a corresponding perceived image depth by,for each given pixel in at least some of the pixels, digitally:calculating a vector between said given pixel and a user pupil location;approximating a direction of a light field emanated by said given pixelbased on a given LFSE intersected by said vector; projecting an adjustedimage ray trace between said given pixel and said given LFSE to identifya corresponding adjusted image location for a first perceived imagedepth given said direction; upon said adjusted image ray traceintersecting said given image portion associated with said firstperceived image depth, associating with said given pixel an adjustedimage portion value designated for said corresponding adjusted imagelocation based on said intersection; otherwise repeating said projectingand associating for a subsequent perceived image depth; and renderingfor each said given pixel said adjusted image portion value associatedtherewith, thereby rendering distinctly perceptively adjusted imageportions.

In one embodiment, the digital display device further comprises a pupiltracker or pupil tracking interface operable to dynamically track andautomatically accommodate for changes in said input user pupil location.

In one embodiment, the array of LFSEs comprises a lenslet array.

In one embodiment, each of said image portions correspond to an optotypethat are rendered side-by-side at distinct perceived image depths.

In accordance with another aspect, there is provided a device forsubjective vision testing of a user having a reduced visual acuity, thedevice comprising: the digital display as described above, wherein eachof said image portions corresponds to an optotype; and wherein thedisplay is operable to simultaneously render said optotype in each ofsaid portions side-by-side at distinct perceived image depths.

In one embodiment, the distinct perceived image depths are dynamicallyvariable via said display to subjectively assess a user's reduced visualacuity.

In one embodiment, the device further comprises a variable opticalsystem disposed in a line-of-sight of the display so to further adjustsaid perceived depth for said rendered image portions.

In accordance with another aspect, there is provided acomputer-implemented method, automatically implemented by one or moredigital processors, to adjust user perception of distinct image portionsto be rendered via a set of pixels and a corresponding array of lightfield shaping elements (LFSE), the method comprising, for each givenpixel of at least some of the set of pixels, digitally: digitallyprojecting an adjusted image ray trace between said given pixel and auser pupil location to intersect an adjusted image location for a givenperceived image depth given a direction of a light field emanated bysaid given pixel based on a given LFSE intersected thereby; upon saidadjusted image ray trace intersecting a given image portion associatedwith said given perceived image depth, associating with said given pixelan adjusted image portion value designated for said adjusted imagelocation based on said intersection; otherwise repeating said projectingand associating for a subsequent perceived image depth and adjustedimage portion associated therewith; and rendering for each said givenpixel said adjusted image portion value associated therewith, therebyrendering distinctly perceptively adjusted image portions perceptivelyrendered at respectively corresponding perceived image depths.

In accordance with another aspect, there is provided a non-transitorycomputer-readable medium comprising digital instructions to beimplemented by one or more digital processors to automatically adjustuser perception of distinct image portions to be rendered on a digitaldisplay via a set of pixels thereof and an array of light field shapingelements (LFSE) disposed relative thereto, by, for each given pixel ofat least some of the set of pixels, digitally: digitally projecting anadjusted image ray trace between said given pixel and a user pupillocation to intersect an adjusted image location for a given perceivedimage depth given a direction of a light field emanated by said givenpixel based on a given LFESE intersected thereby; upon said adjustedimage ray trace intersecting a given image portion associated with saidgiven perceived image depth, associating with said given pixel anadjusted image portion value designated for said adjusted image locationbased on said intersection to be rendered accordingly; otherwiserepeating said projecting and associating for a subsequent perceivedimage depth and adjusted image portion associated therewith; therebyrendering distinctly perceptively adjusted image portions perceptivelyrendered at respectively corresponding perceived image depths.

In one embodiment, the computer-readable medium further comprisesinstructions for, or the method further comprises, prior to saidprojecting: calculating a vector between said given pixel and said userpupil location; and approximating said direction of said light fieldemanated by said given pixel based on said given LFSE intersected bysaid vector.

In one embodiment, each of said image portions is digitally mapped to acorresponding virtual image plane virtually positioned relative to thepixels at said respectively corresponding perceived image depths, andwherein said intersection is defined on said corresponding virtual imageplane.

In one embodiment, each of said image portions is mapped to a userretinal plane in accordance with said given perceived image depth basedon a user eye focus parameter, and wherein said intersection is definedon said retinal plane by redirecting said adjusted image ray trace atsaid pupil location in accordance with said user eye focus parameter.

In one embodiment, the projecting and associating are implemented inparallel for each said given pixel of at least a subset of said pixels.

In one embodiment, the distinct image portions are to be perceptivelyrendered side-by-side at said respectively corresponding perceived imagedepths.

In one embodiment, the distinct image portions are to be perceptivelyrendered side-by-side at said respectively corresponding perceived imagedepths in a 2-dimentional grid or in respective image quadrants.

In one embodiment, each of said image portions correspond to an optotypesimultaneously rendered in each of said portions side-by-side atdistinct perceived image depths to subjectively assess a user's reducedvisual acuity.

In one embodiment, the overlap between said image portions areautomatically addressed by rendering a nearest perceptive depth.

In accordance with another aspect, there is provided a digital displaydevice comprising: an array of pixels; an array of light field shapingelements (LFSEs) to shape a light field emanating from said pixels andthereby at least partially govern a projection thereof from said pixelstoward a given user pupil location; and a hardware processor operable onpixel data for input image portions to output adjusted image pixel datato be rendered via said LFSEs to adjust user perception from said givenuser pupil location of said input image portions as renderedtherethrough and thereby render distinctly perceptively adjusted imageportions at respectively corresponding perceived image depths.

In one embodiment, the hardware processor outputs said adjusted pixeldata as a function of adjusted image ray traces digitally computed foreach given pixel of at least some of the array of pixels that intersectsaid user pupil location.

In one embodiment, the hardware processor is operable to, for each givenpixel of at least some of the array of pixels: digitally project anadjusted image ray trace between said given pixel and said given userpupil location to intersect an adjusted image location for a givenperceived image depth given a direction of a light field emanated bysaid given pixel based on a given LFESE intersected thereby; upon saidadjusted image ray trace intersecting a given image portion associatedwith said given perceived image depth, associate with said given pixelan adjusted image portion value designated for said adjusted imagelocation based on said intersection; otherwise repeat said projectingand associating for a subsequent perceived image depth and adjustedimage portion associated therewith; and render for each said given pixelsaid adjusted image portion value associated therewith, therebyrendering distinctly perceptively adjusted image portions perceptivelyrendered at respectively corresponding perceived image depths.

In one embodiment, the hardware processor is further operable to, priorto said projecting: calculate a vector between said given pixel and saiduser pupil location; and approximate said direction of said light fieldemanated by said given pixel based on said given LFSE intersected bysaid vector.

In one embodiment, each of said image portions is digitally mapped to acorresponding virtual image plane virtually positioned relative to thedigital display at said respectively corresponding perceived imagedepths, and wherein said intersection is defined on said correspondingvirtual image plane.

In one embodiment, each of said image portions is mapped to a userretinal plane in accordance with said given perceived image depth basedon a user eye focus parameter, and wherein said intersection is definedon said retinal plane by redirecting said adjusted image ray trace atsaid pupil location in accordance with said user eye focus parameter.

In one embodiment, the projecting and associating are implemented inparallel for each said given pixel of at least a subset of said pixels.

In one embodiment, the distinct image portions are to be perceptivelyrendered side-by-side at said respectively corresponding perceived imagedepths.

In one embodiment, the distinct image portions are to be perceptivelyrendered side-by-side at said respectively corresponding perceived imagedepths in a 2-dimentional grid or in respective image quadrants.

In one embodiment, each of said image portions correspond to an optotypesimultaneously rendered in each of said portions side-by-side atdistinct perceived image depths to subjectively assess a user's reducedvisual acuity.

In one embodiment, overlap between said image portions are automaticallyaddressed by rendering a nearest perceptive depth.

In one embodiment, the device further comprises a pupil tracker or pupiltracking interface operable to dynamically track and automaticallyaccommodate for changes in said given user pupil location.

In one embodiment, the array of LFSEs comprises a lenslet array.

In one embodiment, each of said distinct perceived image depths aredynamically variable so to subjectively assess the user's reduced visualacuity.

Other aspects, features and/or advantages will become more apparent uponreading of the following non-restrictive description of specificembodiments thereof, given by way of example only with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

Several embodiments of the present disclosure will be provided, by wayof examples only, with reference to the appended drawings, wherein:

FIG. 1 is a diagrammatical view of an electronic device having a digitaldisplay, in accordance with one embodiment;

FIGS. 2A and 2B are exploded and side views, respectively, of anassembly of a light field display for an electronic device, inaccordance with one embodiment;

FIGS. 3A, 3B and 3C schematically illustrate normal vision, blurredvision, and corrected vision in accordance with one embodiment,respectively;

FIG. 4 is a schematic diagram of a single light field pixel defined by aconvex lenslet or microlens overlaying an underlying pixel array anddisposed at or near its focus to produce a substantially collimatedbeam, in accordance with one embodiment;

FIG. 5 is another schematic exploded view of an assembly of a lightfield display in which respective pixel subsets are aligned to emitlight through a corresponding microlens or lenslet, in accordance withone embodiment;

FIG. 6 is an exemplary diagram of a light field pattern that, whenproperly projected by a light field display, produces a corrected imageexhibiting reduced blurring for a viewer having reduced visual acuity,in accordance with one embodiment;

FIGS. 7A and 7B are photographs of a Snellen chart, as illustrativelyviewed by a viewer with reduced acuity without image correction (blurryimage in FIG. 7A) and with image correction via a light field display(corrected image in FIG. 7B), in accordance with one embodiment;

FIG. 8 is a schematic diagram of a portion of a hexagonal lenslet arraydisposed at an angle relative to an underlying pixel array, inaccordance with one embodiment;

FIGS. 9A and 9B are photographs as illustratively viewed by a viewerwith reduced visual acuity without image correction (blurry image inFIG. 9A) and with image correction via a light field display having anangularly mismatched lenslet array (corrected image in FIG. 9B), inaccordance with one embodiment;

FIGS. 10A and 10B are photographs as illustratively viewed by a viewerwith reduced visual acuity without image correction (blurry image inFIG. 10A) and with image correction via a light field display having anangularly mismatched lenslet array (corrected image in FIG. 10B), inaccordance with one embodiment;

FIG. 11 is a process flow diagram of an illustrative ray-tracingrendering process, in accordance with one embodiment;

FIGS. 12 and 13 are process flow diagrams of exemplary input constantparameters and variables, respectively, for the ray-tracing renderingprocess of FIG. 11, in accordance with one embodiment;

FIGS. 14A to 14C are schematic diagrams illustrating certain processsteps of FIG. 11;

FIG. 15 is a process flow diagram of an exemplary process for computingthe center position of an associated light field shaping unit in theray-tracing rendering process of FIG. 11, in accordance with oneembodiment;

FIGS. 16A and 16B are schematic diagrams illustrating an exemplaryhexagonal light field shaping layer with a corresponding hexagonal tilearray, in accordance with one embodiment;

FIGS. 17A and 17B are schematic diagrams illustrating overlaying astaggered rectangular tile array over the hexagonal tile array of FIGS.16A and 16B, in accordance with one embodiment;

FIGS. 18A to 18C are schematic diagrams illustrating the associatedregions of neighboring hexagonal tiles within a single rectangular tile,in accordance with one embodiment;

FIG. 19 is process flow diagram of an illustrative ray-tracing renderingprocess, in accordance with another embodiment;

FIGS. 20A to 20D are schematic diagrams illustrating certain processsteps of FIG. 19;

FIGS. 21A and 21B are schematic diagrams illustrating pixel and subpixelrendering, respectively, in accordance with some embodiments;

FIGS. 22A and 22B are schematic diagrams of an LCD pixel array definedby respective red (R), green (G) and blue (B) subpixels, and renderingan angular image edge using pixel and subpixel rendering, respectively,in accordance with one embodiment;

FIG. 23 is a schematic diagram of one of the pixels of FIG. 22A, showingmeasures for independently accounting for subpixels thereof applysubpixel rendering to the display of a corrected image through a lightfield display, in accordance with one embodiment;

FIG. 24 is a process flow diagram of an illustrative ray-tracingrendering process for rendering a light field originating from multipledistinct virtual image planes, in accordance with one embodiment;

FIG. 25 is a process flow diagram of an exemplary process for iteratingover multiple virtual image planes in the ray-tracing rendering processof FIG. 24, in accordance with one embodiment;

FIGS. 26A to 26D are schematic diagrams illustrating certain processsteps of FIG. 25;

FIG. 27 is a process flow diagram of an illustrative ray-tracingrendering process for rendering a light field originating from multipledistinct virtual image planes, in accordance with one embodiment;

FIG. 28 is a process flow diagram of an exemplary process for iteratingover multiple virtual image planes in the ray-tracing rendering processof FIG. 27, in accordance with one embodiment;

FIGS. 29A and 29B are schematic diagrams illustrating an example of asubjective visual acuity test using the ray-tracing rendering process ofFIGS. 25 or FIG. 27, in accordance with one embodiment;

FIG. 30 is a schematic diagram of an exemplary vision testing system, inaccordance with one embodiment;

FIGS. 31A to 31C are schematic diagrams of exemplary light fieldrefractors/phoropters, in accordance with different embodiments;

FIG. 32 is a plot of the angular resolution of an exemplary light fielddisplay as a function of the dioptric power generated, in accordancewith one embodiment;

FIGS. 33A to 33D are schematic plots of the image quality generated by alight field refractor/phoropter as a function of the dioptric powergenerated by using in combination with the light field display (A) norefractive component, (B) one refractive component, (C) and (D) amultiplicity of refractive components;

FIGS. 34A and 34B are perspective internal views of exemplary lightfield refractors/phoropters showing a casing thereof in cross-section,in accordance with one embodiment;

FIG. 35 is a perspective view of an exemplary light fieldrefractor/phoropter combining side-by-side two of the units shown inFIGS. 34A and 34B for evaluating both eyes at the same time, inaccordance with one embodiment;

FIG. 36 is a process flow diagram of an exemplary dynamic subjectivevision testing method, in accordance with one embodiment;

FIG. 37 is a schematic diagram of an exemplary light field image showingtwo columns of optotypes at different dioptric power for the method ofFIG. 36, in accordance with one embodiment.

Elements in the several figures are illustrated for simplicity andclarity and have not necessarily been drawn to scale. For example, thedimensions of some of the elements in the figures may be emphasizedrelative to other elements for facilitating understanding of the variouspresently disclosed embodiments. Also, common, but well-understoodelements that are useful or necessary in commercially feasibleembodiments are often not depicted in order to facilitate a lessobstructed view of these various embodiments of the present disclosure.

DETAILED DESCRIPTION

Various implementations and aspects of the specification will bedescribed with reference to details discussed below. The followingdescription and drawings are illustrative of the specification and arenot to be construed as limiting the specification. Numerous specificdetails are described to provide a thorough understanding of variousimplementations of the present specification. However, in certaininstances, well-known or conventional details are not described in orderto provide a concise discussion of implementations of the presentspecification.

Various apparatuses and processes will be described below to provideexamples of implementations of the system disclosed herein. Noimplementation described below limits any claimed implementation and anyclaimed implementations may cover processes or apparatuses that differfrom those described below. The claimed implementations are not limitedto apparatuses or processes having all of the features of any oneapparatus or process described below or to features common to multipleor all of the apparatuses or processes described below. It is possiblethat an apparatus or process described below is not an implementation ofany claimed subject matter.

Furthermore, numerous specific details are set forth in order to providea thorough understanding of the implementations described herein.However, it will be understood by those skilled in the relevant artsthat the implementations described herein may be practiced without thesespecific details. In other instances, well-known methods, procedures andcomponents have not been described in detail so as not to obscure theimplementations described herein.

In this specification, elements may be described as “configured to”perform one or more functions or “configured for” such functions. Ingeneral, an element that is configured to perform or configured forperforming a function is enabled to perform the function, or is suitablefor performing the function, or is adapted to perform the function, oris operable to perform the function, or is otherwise capable ofperforming the function.

It is understood that for the purpose of this specification, language of“at least one of X, Y, and Z” and “one or more of X, Y and Z” may beconstrued as X only, Y only, Z only, or any combination of two or moreitems X, Y, and Z (e.g., XYZ, XY, YZ, ZZ, and the like). Similar logicmay be applied for two or more items in any occurrence of “at least one. . . ” and “one or more . . . ” language.

The systems and methods described herein provide, in accordance withdifferent embodiments, different examples of a light field display,adjusted pixel rendering method therefor, and adjusted vision perceptionsystem and method using same. For example, some of the herein-describedembodiments provide improvements or alternatives to current light fielddisplay technologies, for instance, providing for multiple concurrentadjusted image perception planes, depths, and/or focus, which, in someexamples, may result in perceptible 2.5D/3D or adjustable location-basedimage perspective effects, distinctly optimized vision correction toolsor vision corrected 2.5D/3D rendering tools, or again provide tools,equipment, features or solutions for the implementation of subjectivevision tests. For example, a subjective vision (e.g. blur) testing toolcan rely on the herein-described solutions to simultaneously depictdistinct optotypes corresponding to respective optical resolving orcorrective powers in providing a subjective basis for optical testingcomparisons. These and other such applications will be described infurther detail below.

As noted above, the devices, displays and methods described herein mayallow a user's perception of one or more input images (or input imageportions), where each image or image portion is virtually located at adistinct image plane/depth location, to be adjusted or altered using thelight field display. These may be used, as described below, to providevision correction for a user viewing digital displays, but the samelight field displays and rendering technology, as detailed below andaccording to different embodiments, may equally be used or beimplemented in a refractor or phoropter-like device to test, screen,diagnose and/or deduce a patient's reduced visual acuity. In accordancewith some embodiments, different vision testing devices and systems asdescribed herein may be contemplated so to replace or complementtraditional vision testing devices such as refractors and/or phoropters,in which traditional devices different optotypes are shown to a user insequence via changing and/or compounding optical elements (lenses,prisms, etc.) so to identify an optical combination that best improvesthe user's perception of these displayed optotypes. As will be describedin greater detail below, embodiments as described herein introduce lightfield display technologies and image rendering techniques, alone or incombination with complementary optical elements such as refractive lens,prisms, etc., to provide, amongst other benefits, for greater visiontesting versatility, compactness, portability, range, precision, and/orother benefits as will be readily appreciated by the skilled artisan.Accordingly, while the terms light field refractor or phoropter will beused interchangeably herein to reference the implementation of differentembodiments of a more generally defined light field vision testingdevice and system, the person of ordinary skill in the art willappreciate the versatility of the herein described implementation oflight field rendering techniques, and ray tracing approaches detailedherein with respect to some embodiments, in the provision of effectivelight field vision testing devices and systems in general.

As noted above, some of the herein described embodiments provide fordigital display devices, or devices encompassing such displays, for useby users having reduced visual acuity, whereby images ultimatelyrendered by such devices can be dynamically processed to accommodate theuser's reduced visual acuity so that they may consume rendered imageswithout the use of corrective eyewear, as would otherwise be required.Accordingly, such embodiments can be dynamically controlled toprogressively adjust a user's perception of rendered images or imageportions (e.g. optotype within the context of a blur test for example)until an optimized correction is applied that optimizes the user'sperception. Perception adjustment parameters used to achieve thisoptimized perception can then be translated into a proposed visioncorrection prescription to be applied to corrective eyewear. Conversely,a user's vision correction eyewear prescription can be used as input todictate selection of applied vision correction parameters and relatedimage perception adjustment, to validate or possibly further fine tunethe user's prescription, for example, and progressively adjusting suchcorrection parameters to test for the possibility of a furtherimprovement. As noted above, embodiments are not to be limited as suchas the notions and solutions described herein may also be applied toother technologies in which a user's perception of an input image to bedisplayed can be altered or adjusted via the light field display.However, for the sake of illustration, a number of the herein describedembodiments will be described as allowing for implementation ofdigitally adaptive vision tests such that individuals with such reducedvisual acuity can be exposed to distinct perceptively adjusted versionsof an input image(s) (e.g. optotypes) to subjectively ascertain apotentially required or preferred vision correction.

Generally, digital displays as considered herein will comprise a set ofimage rendering pixels and a corresponding set of light field shapingelements that at least partially govern a light field emanated therebyto produce a perceptively adjusted version of the input image, notablydistinct perceptively adjusted portions of an input image or inputscene, which may include distinct portions of a same image, a same2.5D/3D scene, or distinct images (portions) associated with differentimage depths, effects and/or locations and assembled into a combinedvisual input. For simplicity, the following will generally considerdistinctly addressed portions or segments as distinct portions of aninput image, whether that input image comprises a singular image havingdistinctly characterized portions, a digital assembly of distinctlycharacterized images, overlays, backgrounds, foregrounds or the like, orany other such digital image combinations.

In some examples, light field shaping elements may take the form of alight field shaping layer or like array of optical elements to bedisposed relative to the display pixels in at least partially governingthe emanated light field. As described in further detail below, suchlight field shaping layer elements may take the form of a microlensand/or pinhole array, or other like arrays of optical elements, or againtake the form of an underlying light shaping layer, such as anunderlying array of optical gratings or like optical elements operableto produce a directional pixelated output.

Within the context of a light field shaping layer, as described infurther detail below in accordance with some embodiments, the lightfield shaping layer can be disposed at a pre-set distance from thepixelated display so to controllably shape or influence a light fieldemanating therefrom. For instance, each light field shaping layer can bedefined by an array of optical elements centered over a correspondingsubset of the display's pixel array to optically influence a light fieldemanating therefrom and thereby govern a projection thereof from thedisplay medium toward the user, for instance, providing some controlover how each pixel or pixel group will be viewed by the viewer'seye(s). As will be further detailed below, arrayed optical elements mayinclude, but are not limited to, lenslets, microlenses or other suchdiffractive optical elements that together form, for example, a lensletarray; pinholes or like apertures or windows that together form, forexample, a parallax or like barrier; concentrically patterned barriers,e.g. cut outs and/or windows, such as a to define a Fresnel zone plateor optical sieve, for example, and that together form a diffractiveoptical barrier (as described, for example, in Applicant's co-pendingU.S. application Ser. No. 15/910,908, the entire contents of which arehereby incorporated herein by reference); and/or a combination thereof,such as for example, a lenslet array whose respective lenses or lensletsare partially shadowed or barriered around a periphery thereof so tocombine the refractive properties of the lenslet with some of theadvantages provided by a pinhole barrier.

In operation, the display device will also generally invoke a hardwareprocessor operable on image pixel (or subpixel) data for an image to bedisplayed to output corrected or adjusted image pixel data to berendered as a function of a stored characteristic of the light fieldshaping elements and/or layer, e.g. layer distance from display screen,distance between optical elements (pitch), absolute relative location ofeach pixel or subpixel to a corresponding optical element, properties ofthe optical elements (size, diffractive and/or refractive properties,etc.), or other such properties, and a selected vision correction oradjustment parameter related to the user's reduced visual acuity orintended viewing experience. While light field display characteristicswill generally remain static for a given implementation (i.e. a givenshaping element and/or layer will be used and set for each deviceirrespective of the user), image processing can, in some embodiments, bedynamically adjusted as a function of the user's visual acuity orintended application so to actively adjust a distance of a virtual imageplane, or perceived image on the user's retinal plane given a quantifieduser eye focus or like optical aberration(s), induced upon rendering thecorrected/adjusted image pixel data via the static optical layer and/orelements, for example, or otherwise actively adjust image processingparameters as may be considered, for example, when implementing aviewer-adaptive pre-filtering algorithm or like approach (e.g.compressive light field optimization), so to at least in part govern animage perceived by the user's eye(s) given pixel or subpixel-specificlight visible thereby through the layer.

Accordingly, a given device may be adapted to compensate for differentvisual acuity levels and thus accommodate different users and/or uses.For instance, a particular device may be configured to implement and/orrender an interactive graphical user interface (GUI) that incorporates adynamic vision correction scaling function that dynamically adjusts oneor more designated vision correction parameter(s) in real-time inresponse to a designated user interaction therewith via the GUI. Forexample, a dynamic vision correction scaling function may comprise agraphically rendered scaling function controlled by a (continuous ordiscrete) user slide motion or like operation, whereby the GUI can beconfigured to capture and translate a user's given slide motionoperation to a corresponding adjustment to the designated visioncorrection parameter(s) scalable with a degree of the user's given slidemotion operation. These and other examples are described in Applicant'sco-pending U.S. patent application Ser. No. 15/246,255, the entirecontents of which are hereby incorporated herein by reference.

With reference to FIG. 1, and in accordance with one embodiment, adigital display device, generally referred to using the numeral 100,will now be described. In this example, the device 100 is generallydepicted as a smartphone or the like, though other devices encompassinga graphical display may equally be considered, such as tablets,e-readers, watches, televisions, GPS devices, laptops, desktop computermonitors, televisions, smart televisions, handheld video game consolesand controllers, vehicular dashboard and/or entertainment displays, andthe like.

In the illustrated embodiment, the device 100 comprises a processingunit 110, a digital display 120, and internal memory 130. Display 120can be an LCD screen, a monitor, a plasma display panel, an LED or OLEDscreen, or any other type of digital display defined by a set of pixelsfor rendering a pixelated image or other like media or information.Internal memory 130 can be any form of electronic storage, including adisk drive, optical drive, read-only memory, random-access memory, orflash memory, to name a few examples. For illustrative purposes, memory130 has stored in it vision correction application 140, though variousmethods and techniques may be implemented to provide computer-readablecode and instructions for execution by the processing unit in order toprocess pixel data for an image to be rendered in producing correctedpixel data amenable to producing a corrected image accommodating theuser's reduced visual acuity (e.g. stored and executable imagecorrection application, tool, utility or engine, etc.). Other componentsof the electronic device 100 may optionally include, but are not limitedto, one or more rear and/or front-facing camera(s) 150, an accelerometer160 and/or other device positioning/orientation devices capable ofdetermining the tilt and/or orientation of electronic device 100, andthe like.

For example, the electronic device 100, or related environment (e.g.within the context of a desktop workstation, vehicularconsole/dashboard, gaming or e-learning station, multimedia displayroom, etc.) may include further hardware, firmware and/or softwarecomponents and/or modules to deliver complementary and/or cooperativefeatures, functions and/or services. For example, in some embodiment,and as will be described in greater detail below, a pupil/eye trackingsystem may be integrally or cooperatively implemented to improve orenhance corrective image rending by tracking a location of the user'seye(s)/pupil(s) (e.g. both or one, e.g. dominant, eye(s)) and adjustinglight field corrections accordingly. For instance, the device 100 mayinclude, integrated therein or interfacing therewith, one or moreeye/pupil tracking light sources, such as one or more infrared (IR) ornear-IR (NIR) light source(s) to accommodate operation in limitedambient light conditions, leverage retinal retro-reflections, invokecorneal reflection, and/or other such considerations. For instance,different IR/NIR pupil tracking techniques may employ one or more (e.g.arrayed) directed or broad illumination light sources to stimulateretinal retro-reflection and/or corneal reflection in identifying atracking a pupil location. Other techniques may employ ambient or IR/NIRlight-based machine vision and facial recognition techniques tootherwise locate and track the user's eye(s)/pupil(s). To do so, one ormore corresponding (e.g. visible, IR/NIR) cameras may be deployed tocapture eye/pupil tracking signals that can be processed, using variousimage/sensor data processing techniques, to map a 3D location of theuser's eye(s)/pupil(s). In the context of a mobile device, such as amobile phone, such eye/pupil tracking hardware/software may be integralto the device, for instance, operating in concert with integratedcomponents such as one or more front facing camera(s), onboard IR/NIRlight source(s) and the like. In other user environments, such as in avehicular environment, eye/pupil tracking hardware may be furtherdistributed within the environment, such as dash, console, ceiling,windshield, mirror or similarly-mounted camera(s), light sources, etc.

With reference to FIGS. 2A and 2B, the electronic device 100, such asthat illustrated in FIG. 1, is further shown to include a light fieldshaping layer (LFSL) 200 overlaid atop a display 120 thereof and spacedtherefrom via a transparent spacer 310 or other such means as may bereadily apparent to the skilled artisan. An optional transparent screenprotector 320 is also included atop the layer 200.

For the sake of illustration, the following embodiments will bedescribed within the context of a light field shaping layer defined, atleast in part, by a lenslet array comprising an array of microlenses(also interchangeably referred to herein as lenslets) that are eachdisposed at a distance from a corresponding subset of image renderingpixels in an underlying digital display. It will be appreciated thatwhile a light field shaping layer may be manufactured and disposed as adigital screen overlay, other integrated concepts may also beconsidered, for example, where light field shaping elements areintegrally formed or manufactured within a digital screen's integralcomponents such as a textured or masked glass plate, beam-shaping lightsources (e.g. directional light sources and/or backlit integratedoptical grating array) or like component.

Accordingly, each lenslet will predictively shape light emanating fromthese pixel subsets to at least partially govern light rays beingprojected toward the user by the display device. As noted above, otherlight field shaping layers may also be considered herein withoutdeparting from the general scope and nature of the present disclosure,whereby light field shaping will be understood by the person of ordinaryskill in the art to reference measures by which light, that wouldotherwise emanate indiscriminately (i.e. isotropically) from each pixelgroup, is deliberately controlled to define predictable light rays thatcan be traced between the user and the device's pixels through theshaping layer.

For greater clarity, a light field is generally defined as a vectorfunction that describes the amount of light flowing in every directionthrough every point in space. In other words, anything that produces orreflects light has an associated light field. The embodiments describedherein produce light fields from an object that are not “natural” vectorfunctions one would expect to observe from that object. This gives itthe ability to emulate the “natural” light fields of objects that do notphysically exist, such as a virtual display located far behind the lightfield display, which will be referred to now as the ‘virtual image’. Asnoted in the examples below, in some embodiments, light field renderingmay be adjusted to effectively generate a virtual image on a virtualimage plane that is set at a designated distance from an input userpupil location, for example, so to effectively push back, or moveforward, a perceived image relative to the display device inaccommodating a user's reduced visual acuity (e.g. minimum or maximumviewing distance). In yet other embodiments, light field rendering mayrather or alternatively seek to map the input image on a retinal planeof the user, taking into account visual aberrations, so to adaptivelyadjust rendering of the input image on the display device to produce themapped effect. Namely, where the unadjusted input image would otherwisetypically come into focus in front of or behind the retinal plane(and/or be subject to other optical aberrations), this approach allowsto map the intended image on the retinal plane and work therefrom toaddress designated optical aberrations accordingly. Using this approach,the device may further computationally interpret and compute virtualimage distances tending toward infinity, for example, for extreme casesof presbyopia. This approach may also more readily allow, as will beappreciated by the below description, for adaptability to other visualaberrations that may not be as readily modeled using a virtual image andimage plane implementation. In both of these examples, and likeembodiments, the input image is digitally mapped to an adjusted imageplane (e.g. virtual image plane or retinal plane) designated to providethe user with a designated image perception adjustment that at leastpartially addresses designated visual aberrations. Naturally, whilevisual aberrations may be addressed using these approaches, other visualeffects may also be implemented using similar techniques.

In one example, to apply this technology to vision correction, considerfirst the normal ability of the lens in an eye, as schematicallyillustrated in FIG. 3A, where, for normal vision, the image is to theright of the eye (C) and is projected through the lens (B) to the retinaat the back of the eye (A). As comparatively shown in FIG. 3B, the poorlens shape (F) in presbyopia causes the image to be focused past theretina (D) forming a blurry image on the retina (E). The dotted linesoutline the path of a beam of light (G). Naturally, other visualaberrations can and will have different impacts on image formation onthe retina. To address these aberrations, a light field display (K), inaccordance with some embodiments, projects the correct sharp image (H)to the back of the retina for an eye with a lens which otherwise couldnot adjust sufficiently to produce a sharp image. The other two lightfield pixels (I) and (J) are drawn lightly, but would otherwise fill outthe rest of the image.

As will be appreciated by the skilled artisan, a light field as seen inFIG. 3C cannot be produced with a ‘normal’ two-dimensional displaybecause the pixels' light field emits light isotropically. Instead it isnecessary to exercise tight control on the angle and origin of the lightemitted, for example, using a microlens array or other light fieldshaping layer such as a parallax barrier, or combination thereof.

Following with the example of a microlens array, FIG. 4 schematicallyillustrates a single light field pixel defined by a convex microlens (B)disposed at its focus from a corresponding subset of pixels in an LCDdisplay (C) to produce a substantially collimated beam of light emittedby these pixels, whereby the direction of the beam is controlled by thelocation of the pixel(s) relative to the microlens. The single lightfield pixel produces a beam similar to that shown in FIG. 3C where theoutside rays are lighter and the majority inside rays are darker. TheLCD display (C) emits light which hits the microlens (B) and it resultsin a beam of substantially collimated light (A).

Accordingly, upon predictably aligning a particular microlens array witha pixel array, a designated “circle” of pixels will correspond with eachmicrolens and be responsible for delivering light to the pupil throughthat lens. FIG. 5 schematically illustrates an example of a light fielddisplay assembly in which a microlens array (A) sits above an LCDdisplay on a cellphone (C) to have pixels (B) emit light through themicrolens array. A ray-tracing algorithm can thus be used to produce apattern to be displayed on the pixel array below the microlens in orderto create the desired virtual image that will effectively correct forthe viewer's reduced visual acuity. FIG. 6 provides an example of such apattern for the letter “Z”. Examples of such ray-tracing algorithms arediscussed below.

As will be detailed further below, the separation between the microlensarray and the pixel array as well as the pitch of the lenses can beselected as a function of various operating characteristics, such as thenormal or average operating distance of the display, and/or normal oraverage operating ambient light levels.

Further, as producing a light field with angular resolution sufficientfor accommodation correction over the full viewing ‘zone’ of a displaywould generally require an astronomically high pixel density, instead, acorrect light field can be produced, in some embodiments, only at oraround the location of the user's pupils. To do so, the light fielddisplay can be paired with pupil tracking technology to track a locationof the user's eyes/pupils relative to the display. The display can thencompensate for the user's eye location and produce the correct virtualimage, for example, in real time.

In some embodiments, the light field display can render dynamic imagesat over 30 frames per second on the hardware in a smartphone.

In some embodiments, the light field display can display a virtual imageat optical infinity, meaning that any level of accommodation-basedpresbyopia (e.g. first order) can be corrected for.

In some further embodiments, the light field display can both push theimage back or forward, thus allowing for selective image corrections forboth hyperopia (far-sightedness) and myopia (nearsightedness). This willbe further discussed below in the context of a light field visiontesting (e.g. refractor/phoropter) device using the light field display.

In order to demonstrate a working light field solution, and inaccordance with one embodiment, the following test was set up. A camerawas equipped with a simple lens, to simulate the lens in a human eye andthe aperture was set to simulate a normal pupil diameter. The lens wasfocused to 50 cm away and a phone was mounted 25 cm away. This wouldapproximate a user whose minimal seeing distance is 50 cm and isattempting to use a phone at 25 cm.

With reading glasses, +2.0 diopters would be necessary for the visioncorrection. A scaled Snellen chart was displayed on the cellphone and apicture was taken, as shown in FIG. 7A. Using the same cellphone, butwith a light field assembly in front that uses that cellphone's pixelarray, a virtual image compensating for the lens focus is displayed. Apicture was again taken, as shown in FIG. 7B, showing a clearimprovement.

FIGS. 9A and 9B provide another example of results achieved using anexemplary embodiment, in which a colour image was displayed on the LCDdisplay of a Sony™ Xperia™ XZ Premium phone (reported screen resolutionof 3840×2160 pixels with 16:9 ratio and approximately 807 pixel-per-inch(ppi) density) without image correction (FIG. 9A) and with imagecorrection through a square fused silica microlens array set at a 2degree angle relative to the screen's square pixel array and defined bymicrolenses having a 7.0 mm focus and 200 m pitch. In this example, thecamera lens was again focused at 50 cm with the phone positioned 30 cmaway. Another microlens array was used to produce similar results, andconsisted of microlenses having a 10.0 mm focus and 150 m pitch.

FIGS. 10A and 10B provide yet another example or results achieved usingan exemplary embodiment, in which a colour image was displayed on theLCD display of a Sony™ Xperia™ XZ Premium phone without image correction(FIG. 10A) and with image correction through a square fused silicamicrolens array set at a 2 degree angle relative to the screen's squarepixel array and defined by microlenses having a 10.0 mm focus and 150 mpitch. In this example, the camera lens was focused at 66 cm with thephone positioned 40 cm away.

Accordingly, a display device as described above and further exemplifiedbelow, can be configured to render a corrected image via the light fieldshaping layer that accommodates for the user's visual acuity. Byadjusting the image correction in accordance with the user's actualpredefined, set or selected visual acuity level, different users andvisual acuity may be accommodated using a same device configuration.That is, in one example, by adjusting corrective image pixel data todynamically adjust a virtual image distance below/above the display asrendered via the light field shaping layer, different visual acuitylevels may be accommodated.

As will be appreciated by the skilled artisan, different imageprocessing techniques may be considered, such as those introduced aboveand taught by Pamplona and/or Huang, for example, which may alsoinfluence other light field parameters to achieve appropriate imagecorrection, virtual image resolution, brightness and the like.

With reference to FIG. 8, and in accordance with one embodiment, amicrolens array configuration will now be described, in accordance withanother embodiment, to provide light field shaping elements in acorrective light field implementation. In this embodiment, the microlensarray 800 is defined by a hexagonal array of microlenses 802 disposed soto overlay a corresponding square pixel array 804. In doing so, whileeach microlens 802 can be aligned with a designated subset of pixels toproduce light field pixels as described above, the hexagonal-to-squarearray mismatch can alleviate certain periodic optical artifacts that mayotherwise be manifested given the periodic nature of the opticalelements and principles being relied upon to produce the desired opticalimage corrections. Conversely, a square microlens array may be favouredwhen operating a digital display comprising a hexagonal pixel array.

In some embodiments, as illustrated in FIG. 8, the microlens array 800may further or alternatively overlaid at an angle 806 relative to theunderlying pixel array, which can further or alternatively alleviateperiod optical artifacts.

In yet some further or alternative embodiments, a pitch ratio betweenthe microlens array and pixel array may be deliberately selected tofurther or alternatively alleviate periodic optical artifacts. Forexample, a perfectly matched pitch ratio (i.e. an exact integer numberof display pixels per microlens) is most likely to induce periodicoptical artifacts, whereas a pitch ratio mismatch can help reduce suchoccurrences. Accordingly, in some embodiments, the pitch ratio will beselected to define an irrational number, or at least, an irregularratio, so to minimize periodic optical artifacts. For instance, astructural periodicity can be defined so to reduce the number ofperiodic occurrences within the dimensions of the display screen athand, e.g. ideally selected so to define a structural period that isgreater than the size of the display screen being used.

While this example is provided within the context of a microlens array,similar structural design considerations may be applied within thecontext of a parallax barrier, diffractive barrier or combinationthereof.

With reference to FIGS. 11 to 13, and in accordance with one embodiment,an exemplary computationally implemented ray-tracing method forrendering an adjusted image via an array of light field shapingelements, in this example provided by a light field shaping layer (LFSL)disposed relative to a set of underlying display pixels, thataccommodates for the user's reduced visual acuity will now be described.In this example, for illustrative purposes, adjustment of a single image(i.e. the image as whole) is being implemented without consideration fordistinct image portions. Further examples below will specificallyaddress modification of the following example for adaptively adjustingdistinct image portions.

In this exemplary embodiment, a set of constant parameters 1102 may bepre-determined. These may include, for example, any data that are notexpected to significantly change during a user's viewing session, forinstance, which are generally based on the physical and functionalcharacteristics of the display for which the method is to beimplemented, as will be explained below. Similarly, every iteration ofthe rendering algorithm may use a set of input variables 1104 which areexpected to change either at each rendering iteration or at leastbetween each user's viewing session.

As illustrated in FIG. 12, the list of constant parameters 1102 mayinclude, without limitations, the distance 1204 between the display andthe LFSL, the in-plane rotation angle 1206 between the display and LFSLframes of reference, the display resolution 1208, the size of eachindividual pixel 1210, the optical LFSL geometry 1212, the size of eachoptical element 1214 within the LFSL and optionally the subpixel layout1216 of the display. Moreover, both the display resolution 1208 and thesize of each individual pixel 1210 may be used to pre-determine both theabsolute size of the display in real units (i.e. in mm) and thethree-dimensional position of each pixel within the display. In someembodiments where the subpixel layout 1216 is available, the positionwithin the display of each subpixel may also be pre-determined. Thesethree-dimensional location/positions are usually calculated using agiven frame of reference located somewhere within the plane of thedisplay, for example a corner or the middle of the display, althoughother reference points may be chosen. Concerning the optical layergeometry 1212, different geometries may be considered, for example ahexagonal geometry such as the one shown in FIG. 8. Finally, bycombining the distance 1204, the rotation angle 1206, and the geometry1212 with the optical element size 1214, it is possible to similarlypre-determine the three-dimensional location/position of each opticalelement center with respect to the display's same frame of reference.

FIG. 13 meanwhile illustratively lists an exemplary set of inputvariables 1104 for method 1100, which may include any input data fedinto method 1100 that may reasonably change during a user's singleviewing session, and may thus include without limitation: the image(s)to be displayed 1306 (e.g. pixel data such as on/off, colour,brightness, etc.), the three-dimensional pupil location 1308 (e.g. inembodiments implementing active eye/pupil tracking methods) and/or pupilsize 1312 and the minimum reading distance 1310 (e.g. one or moreparameters representative of the user's reduced visual acuity orcondition). In some embodiments, the eye depth 1314 may also be used.The image data 1306, for example, may be representative of one or moredigital images to be displayed with the digital pixel display. Thisimage may generally be encoded in any data format used to store digitalimages known in the art. In some embodiments, images 1306 to bedisplayed may change at a given framerate.

The pupil location 1308, in one embodiment, is the three-dimensionalcoordinates of at least one of the user's pupils' center with respect toa given reference frame, for example a point on the device or display.This pupil location 1308 may be derived from any eye/pupil trackingmethod known in the art. In some embodiments, the pupil location 1308may be determined prior to any new iteration of the rendering algorithm,or in other cases, at a lower framerate. In some embodiments, only thepupil location of a single user's eye may be determined, for example theuser's dominant eye (i.e. the one that is primarily relied upon by theuser). In some embodiments, this position, and particularly the pupildistance to the screen may otherwise or additionally be ratherapproximated or adjusted based on other contextual or environmentalparameters, such as an average or preset user distance to the screen(e.g. typical reading distance for a given user or group of users;stored, set or adjustable driver distance in a vehicular environment;etc.).

In the illustrated embodiment, the minimum reading distance 1310 isdefined as the minimal focus distance for reading that the user's eye(s)may be able to accommodate (i.e. able to view without discomfort). Insome embodiments, different values of the minimum reading distance 1310associated with different users may be entered, for example, as canother adaptive vision correction parameters be considered depending onthe application at hand and vision correction being addressed. In someembodiments, minimum reading distance 1310 may be derived from an eyeprescription (e.g. glasses prescription or contact prescription) orsimilar. It may, for example, correspond to the near point distancecorresponding to the uncorrected user's eye, which can be calculatedfrom the prescribed corrective lens power assuming that the targetednear point was at 25 cm.

With added reference to FIGS. 14A to 14C, once parameters 1102 andvariables 1104 have been set, the method of FIG. 11 then proceeds withstep 1106, in which the minimum reading distance 1310 (and/or relatedparameters) is used to compute the position of a virtual (adjusted)image plane 1405 with respect to the device's display, followed by step1108 wherein the size of image 1306 is scaled within the image plane1405 to ensure that it correctly fills the pixel display 1401 whenviewed by the distant user. This is illustrated in FIG. 14A, which showsa diagram of the relative positioning of the user's pupil 1415, thelight field shaping layer 1403, the pixel display 1401 and the virtualimage plane 1405. In this example, the size of image 1306 in image plane1405 is increased to avoid having the image as perceived by the userappear smaller than the display's size.

An exemplary ray-tracing methodology is described in steps 1110 to 1128of FIG. 11, at the end of which the output color of each pixel of pixeldisplay 1401 is known so as to virtually reproduce the light fieldemanating from an image 1306 positioned at the virtual image plane 1405.In FIG. 11, these steps are illustrated in a loop over each pixel inpixel display 1401, so that each of steps 1110 to 1126 describes thecomputations done for each individual pixel. However, in someembodiments, these computations need not be executed sequentially, butrather, steps 1110 to 1128 may be executed in parallel for each pixel ora subset of pixels at the same time. Indeed, as will be discussed below,this exemplary method is well suited to vectorization and implementationon highly parallel processing architectures such as GPUs.

As illustrated in FIG. 14A, in step 1110, for a given pixel 1409 inpixel display 1401, a trial vector 1413 is first generated from thepixel's position to the center position 1417 of pupil 1415. This isfollowed in step 1112 by calculating the intersection point 1411 ofvector 1413 with the LFSL 1403.

The method then finds, in step 1114, the coordinates of the center 1416of the LFSL optical element closest to intersection point 1411. Thisstep may be computationally intensive and will be discussed in moredepth below. Once the position of the center 1416 of the optical elementis known, in step 1116, a normalized unit ray vector is generated fromdrawing and normalizing a vector 1423 drawn from center position 1416 topixel 1409. This unit ray vector generally approximates the direction ofthe light field emanating from pixel 1409 through this particular lightfield element, for instance, when considering a parallax barrieraperture or lenslet array (i.e. where the path of light travellingthrough the center of a given lenslet is not deviated by this lenslet).Further computation may be required when addressing more complex lightshaping elements, as will be appreciated by the skilled artisan. Thedirection of this ray vector will be used to find the portion of image1306, and thus the associated color, represented by pixel 1409. Butfirst, in step 1118, this ray vector is projected backwards to the planeof pupil 1415, and then in step 1120, the method verifies that theprojected ray vector 1425 is still within pupil 1415 (i.e. that the usercan still “see” it). Once the intersection position, for examplelocation 1431 in FIG. 14B, of projected ray vector 1425 with the pupilplane is known, the distance between the pupil center 1417 and theintersection point 1431 may be calculated to determine if the deviationis acceptable, for example by using a pre-determined pupil size andverifying how far the projected ray vector is from the pupil center.

If this deviation is deemed to be too large (i.e. light emanating frompixel 1409 channeled through optical element 1416 is not perceived bypupil 1415), then in step 1122, the method flags pixel 1409 asunnecessary and to simply be turned off or render a black color.Otherwise, as shown in FIG. 14C, in step 1124, the ray vector isprojected once more towards virtual image plane 1405 to find theposition of the intersection point 1423 on image 1306. Then in step1126, pixel 1409 is flagged as having the color value associated withthe portion of image 1306 at intersection point 1423.

In some embodiments, method 1100 is modified so that at step 1120,instead of having a binary choice between the ray vector hitting thepupil or not, one or more smooth interpolation function (i.e. linearinterpolation, Hermite interpolation or similar) are used to quantifyhow far or how close the intersection point 1431 is to the pupil center1417 by outputting a corresponding continuous value between 1 or 0. Forexample, the assigned value is equal to 1 substantially close to pupilcenter 1417 and gradually change to 0 as the intersection point 1431substantially approaches the pupil edges or beyond. In this case, thebranch containing step 1122 is ignored and step 1220 continues to step1124. At step 1126, the pixel color value assigned to pixel 1409 ischosen to be somewhere between the full color value of the portion ofimage 1306 at intersection point 1423 or black, depending on the valueof the interpolation function used at step 1120 (1 or 0).

In yet other embodiments, pixels found to illuminate a designated areaaround the pupil may still be rendered, for example, to produce a bufferzone to accommodate small movements in pupil location, for example, oragain, to address potential inaccuracies, misalignments or to create abetter user experience.

In some embodiments, steps 1118, 1120 and 1122 may be avoidedcompletely, the method instead going directly from step 1116 to step1124. In such an exemplary embodiment, no check is made that the rayvector hits the pupil or not, but instead the method assumes that italways does.

Once the output colors of all pixels have been determined, these arefinally rendered in step 1130 by pixel display 1401 to be viewed by theuser, therefore presenting a light field corrected image. In the case ofa single static image, the method may stop here. However, new inputvariables may be entered and the image may be refreshed at any desiredfrequency, for example because the user's pupil moves as a function oftime and/or because instead of a single image a series of images aredisplayed at a given framerate.

With reference to FIGS. 19 and 20A to 20D, and in accordance with oneembodiment, another exemplary computationally implemented ray-tracingmethod for rendering an adjusted image via the light field shaping layer(LFSL) that accommodates for the user's reduced visual acuity, forexample, will now be described. Again, for illustrative purposes, inthis example, adjustment of a single image (i.e. the image as whole) isbeing implemented without consideration for distinct image portions.Further examples below will specifically address modification of thefollowing example for adaptively adjusting distinct image portions.

In this embodiment, the adjusted image portion associated with a givenpixel/subpixel is computed (mapped) on the retina plane instead of thevirtual image plane considered in the above example, again in order toprovide the user with a designated image perception adjustment.Therefore, the currently discussed exemplary embodiment shares somesteps with the method of FIG. 11. Indeed, a set of constant parameters1102 may also be pre-determined. These may include, for example, anydata that are not expected to significantly change during a user'sviewing session, for instance, which are generally based on the physicaland functional characteristics of the display for which the method is tobe implemented, as will be explained below. Similarly, every iterationof the rendering algorithm may use a set of input variables 1104 whichare expected to change either at each rendering iteration or at leastbetween each user viewing session. The list of possible variables andconstants is substantially the same as the one disclosed in FIGS. 12 and13 and will thus not be replicated here.

Once parameters 1102 and variables 1104 have been set, this secondexemplary ray-tracing methodology proceeds from steps 1910 to 1936, atthe end of which the output color of each pixel of the pixel display isknown so as to virtually reproduce the light field emanating from animage perceived to be positioned at the correct or adjusted imagedistance, in one example, so to allow the user to properly focus on thisadjusted image (i.e.

having a focused image projected on the user's retina) despite aquantified visual aberration. In FIG. 19, these steps are illustrated ina loop over each pixel in pixel display 1401, so that each of steps 1910to 1934 describes the computations done for each individual pixel.However, in some embodiments, these computations need not be executedsequentially, but rather, steps 1910 to 1934 may be executed in parallelfor each pixel or a subset of pixels at the same time. Indeed, as willbe discussed below, this second exemplary method is also well suited tovectorization and implementation on highly parallel processingarchitectures such as GPUs.

Referencing once more FIG. 14A, in step 1910 (as in step 1110), for agiven pixel in pixel display 1401, a trial vector 1413 is firstgenerated from the pixel's position to pupil center 1417 of the user'spupil 1415. This is followed in step 1912 by calculating theintersection point of vector 1413 with optical layer 1403.

From there, in step 1914, the coordinates of the optical element center1416 closest to intersection point 1411 are determined. This step may becomputationally intensive and will be discussed in more depth below. Asshown in FIG. 14B, once the position of the optical element center 1416is known, in step 1916, a normalized unit ray vector is generated fromdrawing and normalizing a vector 1423 drawn from optical element center1416 to pixel 1409. This unit ray vector generally approximates thedirection of the light field emanating from pixel 1409 through thisparticular light field element, for instance, when considering aparallax barrier aperture or lenslet array (i.e.

where the path of light travelling through the center of a given lensletis not deviated by this lenslet). Further computation may be requiredwhen addressing more complex light shaping elements, as will beappreciated by the skilled artisan. In step 1918, this ray vector isprojected backwards to pupil 1415, and then in step 1920, the methodensures that the projected ray vector 1425 is still within pupil 1415(i.e. that the user can still “see” it). Once the intersection position,for example location 1431 in FIG. 14B, of projected ray vector 1425 withthe pupil plane is known, the distance between the pupil center 1417 andthe intersection point 1431 may be calculated to determine if thedeviation is acceptable, for example by using a pre-determined pupilsize and verifying how far the projected ray vector is from the pupilcenter.

Now referring to FIGS. 20A to 20D, steps 1921 to 1929 of method 1900will be described. Once optical element center 1416 of the relevantoptical unit has been determined, at step 1921, a vector 2004 is drawnfrom optical element center 1416 to pupil center 1417. Then, in step1923, vector 2004 is projected further behind the pupil plane onto focalplane 2006 (location where any light rays originating from optical layer1403 would be focused by the eye) to locate focal point 2008. For a userwith perfect vision, focal plane 2006 would be located at the samelocation as retina plane 2010, but in this example, focal plane 2006 islocated behind retina plane 2010, which would be expected for a userwith some form of farsightedness. The position of focal plane 2006 maybe derived from the user's minimum reading distance 1310, for example,by deriving therefrom the focal length of the user's eye. Other manuallyinput or computationally or dynamically adjustable means may also oralternatively be considered to quantify this parameter.

The skilled artisan will note that any light ray originating fromoptical element center 1416, no matter its orientation, will also befocused onto focal point 2008, to a first approximation. Therefore, thelocation on retina plane 2010 onto which light entering the pupil atintersection point 1431 will converge may be approximated by drawing astraight line between intersection point 1431 where ray vector 1425 hitsthe pupil 1415 and focal point 2008 on focal plane 2006. Theintersection of this line with retina plane 2010 (retina image point2012) is thus the location on the user's retina corresponding to theimage portion that will be reproduced by corresponding pixel 1409 asperceived by the user. Therefore, by comparing the relative position ofretina point 2012 with the overall position of the projected image onthe retina plane 2010, the relevant adjusted image portion associatedwith pixel 1409 may be computed.

To do so, at step 1927, the corresponding projected image centerposition on retina plane 2010 is calculated. Vector 2016 is generatedoriginating from the center position of display 1401 (display centerposition 2018) and passing through pupil center 1417. Vector 2016 isprojected beyond the pupil plane onto retina plane 2010, wherein theassociated intersection point gives the location of the correspondingretina image center 2020 on retina plane 2010. The skilled technicianwill understand that step 1927 could be performed at any moment prior tostep 1929, once the relative pupil center location 1417 is known ininput variables step 1904. Once image center 2020 is known, one can thenfind the corresponding image portion of the selected pixel/subpixel atstep 1929 by calculating the x/y coordinates of retina image point 2012relative to retina image center 2020 on the retina, scaled to the x/yretina image size 2031.

This retina image size 2031 may be computed by calculating themagnification of an individual pixel on retina plane 2010, for example,which may be approximately equal to the x or y dimension of anindividual pixel multiplied by the eye depth 1314 and divided by theabsolute value of the distance to the eye (i.e. the magnification ofpixel image size from the eye lens). Similarly, for comparison purposes,the input image is also scaled by the image x/y dimensions to produce acorresponding scaled input image 2064. Both the scaled input image andscaled retina image should have a width and height between −0.5 to 0.5units, enabling a direct comparison between a point on the scaled retinaimage 2010 and the corresponding scaled input image 2064, as shown inFIG. 20D.

From there, the image portion position 2041 relative to retina imagecenter position 2043 in the scaled coordinates (scaled input image 2064)corresponds to the inverse (because the image on the retina is inverted)scaled coordinates of retina image point 2012 with respect to retinaimage center 2020. The associated color with image portion position 2041is therefrom extracted and associated with pixel 1409.

In some embodiments, method 1900 may be modified so that at step 1920,instead of having a binary choice between the ray vector hitting thepupil or not, one or more smooth interpolation function (i.e. linearinterpolation, Hermite interpolation or similar) are used to quantifyhow far or how close the intersection point 1431 is to the pupil center1417 by outputting a corresponding continuous value between 1 or 0. Forexample, the assigned value is equal to 1 substantially close to pupilcenter 1417 and gradually change to 0 as the intersection point 1431substantially approaches the pupil edges or beyond. In this case, thebranch containing step 1122 is ignored and step 1920 continues to step1124. At step 1931, the pixel color value assigned to pixel 1409 ischosen to be somewhere between the full color value of the portion ofimage 1306 at intersection point 1423 or black, depending on the valueof the interpolation function used at step 1920 (1 or 0).

In yet other embodiments, pixels found to illuminate a designated areaaround the pupil may still be rendered, for example, to produce a bufferzone to accommodate small movements in pupil location, for example, oragain, to address potential inaccuracies or misalignments.

Once the output colors of all pixels in the display have been determined(check at step 1934 is true), these are finally rendered in step 1936 bypixel display 1401 to be viewed by the user, therefore presenting alight field corrected image. In the case of a single static image, themethod may stop here. However, new input variables may be entered andthe image may be refreshed at any desired frequency, for example becausethe user's pupil moves as a function of time and/or because instead of asingle image a series of images are displayed at a given framerate.

As will be appreciated by the skilled artisan, selection of the adjustedimage plane onto which to map the input image in order to adjust a userperception of this input image allows for different ray tracingapproaches to solving a similar challenge, that is of creating anadjusted image using the light field display that can provide anadjusted user perception, such as addressing a user's reduce visualacuity. While mapping the input image to a virtual image plane set at adesignated minimum (or maximum) comfortable viewing distance can provideone solution, the alternate solution may allow accommodation ofdifferent or possibly more extreme visual aberrations. For example,where a virtual image is ideally pushed to infinity (or effectively so),computation of an infinite distance becomes problematic. However, bydesignating the adjusted image plane as the retinal plane, theillustrative process of FIG. 19 can accommodate the formation of avirtual image effectively set at infinity without invoking suchcomputational challenges. Likewise, while first order focal lengthaberrations are illustratively described with reference to FIG. 19,higher order or other optical anomalies may be considered within thepresent context, whereby a desired retinal image is mapped out andtraced while accounting for the user's optical aberration(s) so tocompute adjusted pixel data to be rendered in producing that image.These and other such considerations should be readily apparent to theskilled artisan.

While the computations involved in the above described ray-tracingalgorithms (steps 1110 to 1128 of FIG. 11 or steps 1920 to 1934 of FIG.19) may be done on general CPUs, it may be advantageous to use highlyparallel programming schemes to speed up such computations. While insome embodiments, standard parallel programming libraries such asMessage Passing Interface (MPI) or OPENMP may be used to accelerate thelight field rendering via a general-purpose CPU, the light fieldcomputations described above are especially tailored to take advantageof graphical processing units (GPU), which are specifically tailored formassively parallel computations. Indeed, modern GPU chips arecharacterized by the very large number of processing cores, and aninstruction set that is commonly optimized for graphics. In typical use,each core is dedicated to a small neighborhood of pixel values within animage, e.g., to perform processing that applies a visual effect, such asshading, fog, affine transformation, etc. GPUs are usually alsooptimized to accelerate exchange of image data between such processingcores and associated memory, such as RGB frame buffers. Furthermore,smartphones are increasingly being equipped with powerful GPUs to speedthe rendering of complex screen displays, e.g., for gaming, video, andother image-intensive applications. Several programming frameworks andlanguages tailored for programming on GPUs include, but are not limitedto, CUDA, OpenCL, OpenGL Shader Language (GLSL), High-Level

Shader Language (HLSL) or similar. However, using GPUs efficiently maybe challenging and thus require creative steps to leverage theircapabilities, as will be discussed below.

With reference to FIGS. 15 to 18C and in accordance with one exemplaryembodiment, an exemplary process for computing the center position of anassociated light field shaping element in the ray-tracing process ofFIG. 11 (or FIG. 19) will now be described. The series of steps arespecifically tailored to avoid code branching, so as to be increasinglyefficient when run on GPUs (i.e. to avoid so called “warp divergence”).Indeed, with GPUs, because all the processors must execute identicalinstructions, divergent branching can result in reduced performance.

With reference to FIG. 15, and in accordance with one embodiment, step1114 of FIG. 11 is expanded to include steps 1515 to 1525. A similardiscussion can readily be made in respect of step 1914 of FIG. 19, andthus need not be explicitly detailed herein. The method receives fromstep 1112 the 2D coordinates of the intersection point 1411 (illustratedin FIG. 14A) of the trial vector 1413 with optical layer 1403. Asdiscussed with respect to the exemplary embodiment of FIG. 8, there maybe a difference in orientation between the frames of reference of theoptical layer (hexagonal array of microlenses 802 in FIG. 8, forexample) and of the corresponding pixel display (square pixel array 804in FIG. 8, for example). This is why, in step 1515, these inputintersection coordinates, which are initially calculated from thedisplay's frame of reference, may first be rotated to be expressed fromthe light field shaping layer's frame of reference and optionallynormalized so that each individual light shaping element has a width andheight of 1 unit. The following description will be equally applicableto any light field shaping layer having a hexagonal geometry like theexemplary embodiment of FIG. 8. Note however that the method steps 1515to 1525 described herein may be equally applied to any kind of lightfield shaping layer sharing the same geometry (i.e. not only a microlensarray, but pinhole arrays as well, etc.). Likewise, while the followingexample is specific to an exemplary hexagonal array of LFSL elementsdefinable by a hexagonal tile array of regular hexagonal tiles, othergeometries may also benefit from some or all of the features and/oradvantages of the herein-described and illustrated embodiments. Forexample, different hexagonal LFSL element arrays, such asstretched/elongated, skewed and/or rotated arrays may be considered, ascan other nestled array geometries in which adjacent rows and/or columnsof the LFSL array at least partially “overlap” or inter-nest. Forinstance, as will be described further below, hexagonal arrays and likenestled array geometries will generally provide for a commensuratelysized rectangular/square tile of an overlaid rectangular/square array orgrid to naturally encompass distinct regions as defined by two or moreadjacent underlying nestled array tiles, which can be used to advantagein the examples provided below. In yet other embodiments, the processesdiscussed herein may be applied to rectangular and/or square LFSLelement arrays. Other LFSL element array geometries may also beconsidered, as will be appreciated by the skilled artisan upon readingof the following example, without departing from the general scope andnature of the present disclosure.

For hexagonal geometries, as illustrated in FIGS. 16A and 16B, thehexagonal symmetry of the light field shaping layer 1403 may berepresented by drawing an array of hexagonal tiles 1601, each centeredon their respective light field shaping element, so that the center of ahexagonal tile element is more or less exactly the same as the centerposition of its associated light field shaping element. Thus, theoriginal problem is translated to a slightly similar one whereby one nowneeds to find the center position 1615 of the associated hexagonal tile1609 closest to the intersection point 1411, as shown in FIG. 16B.

To solve this problem, the array of hexagonal tiles 1601 may besuperimposed on or by a second array of staggered rectangular tiles1705, in such a way as to make an “inverted house” diagram within eachrectangle, as clearly illustrated in FIG. 17A, namely defining threelinearly segregated tile regions for each rectangular tile, one regionpredominantly associated with a main underlying hexagonal tile, and twoother opposed triangular regions associated with adjacent underlyinghexagonal tiles. In doing so, the nestled hexagonal tile geometry istranslated to a rectangular tile geometry having distinct linearlysegregated tile regions defined therein by the edges of underlyingadjacently disposed hexagonal tiles. Again, while regular hexagons areused to represent the generally nestled hexagonal LFSL element arraygeometry, other nestled tile geometries may be used to representdifferent nestled element geometries. Likewise, while a nestled array isshown in this example, different staggered or aligned geometries mayalso be used, in some examples, in some respects, with reducedcomplexity, as further described below.

Furthermore, while this particular example encompasses the definition oflinearly defined tile region boundaries, other boundary types may alsobe considered provided they are amenable to the definition of one ormore conditional statements, as illustrated below, that can be used tooutput a corresponding set of binary or Boolean values that distinctlyidentify a location of a given point within one or another of theseregions, for instance, without invoking, or by limiting, processingdemands common to branching or looping decisionlogics/trees/statements/etc.

Following with hexagonal example, to locate the associated hexagon tilecenter 1615 closest to the intersection point 1411, in step 1517, themethod first computes the 2D position of the bottom left corner 1707 ofthe associated (normalized) rectangular tile element 1709 containingintersection point 1411, as shown in FIG. 17B, which can be calculatedwithout using any branching statements by the following two equations(here in normalized coordinates wherein each rectangle has a height andwidth of one unit):

{right arrow over (t)}=(floor(uv _(y)), 0)

{right arrow over (C)}_(corner)=({right arrow over (uv)}+{right arrowover (t)})−{right arrow over (t)}

where {right arrow over (uv)} is the position vector of intersectionpoint 1411 in the common frame of reference of the hexagonal andstaggered rectangular tile arrays, and the floor( ) function returns thegreatest integer less than or equal to each of the xy coordinates of{right arrow over (uv)}.

Once the position of lower left corner 1707, indicated by vector {rightarrow over (C)}_(corner) 1701, of the associated rectangular element1814 containing the intersection point 1411 is known, three regions1804, 1806 and 1807 within this rectangular element 1814 may bedistinguished, as shown in FIGS. 18A to 18C. Each region is associatedwith a different hexagonal tile, as shown in FIG. 18A, namely, eachregion is delineated by the linear boundaries of adjacent underlyinghexagonal tiles to define one region predominantly associated with amain hexagonal tile, and two opposed triangular tiles defined byadjacent hexagonal tiles on either side of this main tile. As will beappreciated by the skilled artisan, different hexagonal or nestled tilegeometries will result in the delineation of different rectangular tileregion shapes, as will different boundary profiles (straight vs. curved)will result in the definition of different boundary value statements,defined further below.

Continuing with the illustrated example, in step 1519, the coordinateswithin associated rectangular tile 1814 are again rescaled, as shown onthe axis of FIG. 18B, so that the intersection point's location, withinthe associated rectangular tile, is now represented in the rescaledcoordinates by a vector {right arrow over (d)} where each of its x and ycoordinates are given by:

d_(x)=2*(uv _(x) −C _(corner) _(x) )−1

d _(y)=3*(uv _(y) −C _(corner) _(y) )

Thus, the possible x and y values of the position of intersection point1411 within associated rectangular tile 1814 are now contained within−1<x<1 and 0<y<3. This will make the next step easier to compute.

To efficiently find the region encompassing a given intersection pointin these rescaled coordinates, the fact that, within the rectangularelement 1814, each region is separated by a diagonal line is used. Forexample, this is illustrated in FIG. 18B, wherein the lower left region1804 is separated from the middle “inverted house” region 1806 and lowerright region 1808 by a downward diagonal line 1855, which in therescaled coordinates of FIG. 18B, follows the simple equation y=−x.Thus, all points where x<−y are located in the lower left region.Similarly, the lower right region 1808 is separated from the other tworegions by a diagonal line 1857 described by the equation y<x.Therefore, in step 1521, the associated region containing theintersection point is evaluated by using these two simple conditionalstatements. The resulting set of two Boolean values will thus bespecific to the region where the intersection point is located. Forexample, the checks (caseL=x<y, caseR=y<x) will result in the values(caseL=true, caseR=false), (caseL=false, caseR=true) and (caseL=false,caseR=false) for intersection points located in the lower left region1804, lower right region 1808 and middle region 1806, respectively. Onemay then convert these Boolean values to floating points values, whereinusually in most programming languages true/false Boolean values areconverted into 1.0/0.0 floating point values. Thus, one obtains the set(caseL, caseR) of values of (1.0, 0.0), (0.0, 1.0) or (0.0, 0.0) foreach of the described regions above.

To finally obtain the relative coordinates of the hexagonal centerassociated with the identified region, in step 1523, the set ofconverted Boolean values may be used as an input to a single floatingpoint vectorial function operable to map each set of these values to aset of xy coordinates of the associated element center. For example, inthe described embodiment and as shown in FIG. 18C, one obtains therelative position vectors of each hexagonal center {right arrow over(r)} with the vectorial function:

{right arrow over (r)}=(r _(x) ,r _(y))=(0.5+0.5*(caseR−caseL),⅔−(caseR−caseL)

thus, the inputs of (1.0, 0.0), (0.0, 1.0) or (0.0, 0.0) map to thepositions (0.0, −⅓), (0.5, ⅔), and (1.0, −⅓), respectively, whichcorresponds to the shown hexagonal centers 1863, 1865 and 1867 shown inFIG. 18C, respectively, in the rescaled coordinates.

Now back to FIG. 15, we may proceed with the final step 1525 totranslate the relative coordinates obtained above to absolute 3Dcoordinates with respect to the display or similar (i.e. in mm). First,the coordinates of the hexagonal tile center and the coordinates of thebottom left corner are added to get the position of the hexagonal tilecenter in the optical layer's frame of reference. As needed, the processmay then scale back the values into absolute units (i.e. mm) and rotatethe coordinates back to the original frame of reference with respect tothe display to obtain the 3D positions (in mm) of the optical layerelement's center with respect to the display's frame of reference, whichis then fed into step 1116.

The skilled artisan will note that modifications to the above-describedmethod may also be used. For example, the staggered grid shown in FIG.17A may be translated higher by a value of 1/3 (in normalized units) sothat within each rectangle the diagonals separating each region arelocated on the upper left and right corners instead. The same generalprinciples described above still applies in this case, and the skilledtechnician will understand the minimal changes to the equations givenabove will be needed to proceed in such a fashion. Furthermore, as notedabove, different LFSL element geometries can result in the delineationof different (normalized) rectangular tile regions, and thus, theformation of corresponding conditional boundary statements and resultingbinary/Boolean region-identifying and center-locating coordinatesystems/functions.

In yet other embodiments, wherein a rectangular and/or square microlensarray is used instead of a nestled (hexagonal) array, a slightlydifferent method may be used to identify the associated LFSL element(microlens) center (step 1114). Herein, the microlens array isrepresented by an array of rectangular and/or square tiles. The method,as previously described, goes through step 1515, where the x and ycoordinates are rescaled (normalized) with respect to a microlens x andy dimension (henceforth giving each rectangular and/or square tile awidth and height of 1 unit). However, at step 1517, the floor( )function is used directly on each x and y coordinates of {right arrowover (uv)} (the position vector of intersection point 1411) to find thecoordinates of the bottom left corner associated with the correspondingsquare/rectangular tile. Therefrom, the relative coordinates of the tilecenter from the bottom left corner are added directly to obtain thefinal scaled position vector:

{right arrow over (r)}=(r _(x) ,r _(y))=(floor(uv _(x))+0.5, floor(uv_(y))+0.5)

Once this vector is known, the method goes directly to step 1525 wherethe coordinates are scaled back into absolute units (i.e. mm) androtated back to the original frame of reference with respect to thedisplay to obtain the 3D positions (in mm) of the optical layerelement's center with respect to the display's frame of reference, whichis then fed into step 1116.

The light field rendering methods described above (from FIGS. 11 to 20D)may also be applied, in some embodiments, at a subpixel level in orderto achieve an improved light field image resolution. Indeed, a singlepixel on a color subpixelated display is typically made of several colorprimaries, typically three colored elements—ordered (on variousdisplays) either as blue, green and red (BGR) or as red, green and blue(RGB). Some displays have more than three primaries such as thecombination of red, green, blue and yellow (RGBY) or red, green, blueand white (RGBW), or even red, green, blue, yellow and cyan (RGBYC).Subpixel rendering operates by using the subpixels as approximatelyequal brightness pixels perceived by the luminance channel. This allowsthe subpixels to serve as sampled image reconstruction points as opposedto using the combined subpixels as part of a “true” pixel. For the lightfield rendering methods as described above, this means that the centerposition of a given pixel (e.g. pixel 1401 in FIG. 14) is replaced bythe center positions of each of its subpixel elements. Therefore, thenumber of color samples to be extracted is multiplied by the number ofsubpixels per pixel in the digital display. The methods may then followthe same steps as described above and extract the associated imageportions of each subpixel individually (sequentially or in parallel).

In FIG. 21A, an exemplary pixel 2115 is comprised of three RGB subpixels(2130 for red, 2133 for green and 2135 for blue). Other embodiments maydeviate from this color partitioning, without limitation. When renderingper pixel, as described in FIG. 11 or in FIG. 19, the image portion 2145associated with said pixel 2115 is sampled to extract the luminancevalue of each RGB color channels 2157, which are then all rendered bythe pixel at the same time. In the case of subpixel rendering, asillustrated in FIG. 21B, the methods find the image portion 2147associated with blue subpixel 2135. Therefore, only the subpixel channelintensity value of RGB color channels 2157 corresponding to the targetsubpixel 2135 is used when rendering (herein the blue subpixel colorvalue, the other two values are discarded). In doing so, a higheradjusted image resolution may be achieved for instance, by adjustingadjusted image pixel colours on a subpixel basis, and also optionallydiscarding or reducing an impact of subpixels deemed not to intersect orto only marginally intersect with the user's pupil.

To further illustrate embodiments making use of subpixel rendering, withreference to FIGS. 22A and 22B, a (LCD) pixel array 2200 isschematically illustrated to be composed of an array of display pixels2202 each comprising red (R) 2204, green (G) 2206, and blue (B) 2208subpixels. As with the examples provided above, to produce a light fielddisplay, a light field shaping layer, such as a microlens array, is tobe aligned to overlay these pixels such that a corresponding subset ofthese pixels can be used to predictably produce respective light fieldrays to be computed and adjusted in providing a corrected image. To doso, the light field ray ultimately produced by each pixel can becalculated knowing a location of the pixel (e.g. x,y coordinate on thescreen), a location of a corresponding light field element through whichlight emanating from the pixel will travel to reach the user's eye(s),and optical characteristics of that light field element, for example.Based on those calculations, the image correction algorithm will computewhich pixels to light and how, and output subpixel lighting parameters(e.g. R, G and B values) accordingly. As noted above, to reducecomputation load, only those pixels producing rays that will interfacewith the user's eyes or pupils may be considered, for instance, using acomplementary eye tracking engine and hardware, though other embodimentsmay nonetheless process all pixels to provide greater buffer zonesand/or a better user experience.

In the example shown in FIG. 22A, an angular edge 2209 is being renderedthat crosses the surfaces of affected pixels 2210, 2212, 2214 and 2216.Using standard pixel rendering, each affected pixel is either turned onor off, which to some extent dictates a relative smoothness of theangular edge 2209.

In the example shown in FIG. 22B, subpixel rendering is insteadfavoured, whereby the red subpixel in pixel 2210, the red and greensubpixels in pixel 2214 and the red subpixel in pixel 2216 aredeliberately set to zero (0) to produce a smoother representation of theangular edge 2209 at the expense of colour trueness along that edge,which will not be perceptible to the human eye given the scale at whichthese modifications are being applied. Accordingly, image correction canbenefit from greater subpixel control while delivering sharper images.

In order to implement subpixel rendering in the context of light fieldimage correction, in some embodiments, ray tracing calculations must beexecuted in respect of each subpixel, as opposed to in respect of eachpixel as a whole, based on a location (x,y coordinates on the screen) ofeach subpixel. Beyond providing for greater rendering accuracy andsharpness, subpixel control and ray tracing computations may accommodatedifferent subpixel configurations, for example, where subpixel mixing oroverlap is invoked to increase a perceived resolution of a highresolution screen and/or where non-uniform subpixel arrangements areprovided or relied upon in different digital display technologies.

In some embodiments, however, in order to avoid or reduce a computationload increase imparted by the distinct consideration of each subpixel,some computation efficiencies may be leveraged by taking into accountthe regular subpixel distribution from pixel to pixel, or in the contextof subpixel sharing and/or overlap, for certain pixel groups, lines,columns, etc. With reference to FIG. 23, a given pixel 2300, much asthose illustrated in FIGS. 22A and 22B, is shown to include horizontallydistributed red (R) 2304, green (G) 2306, and blue (B) 2308 subpixels.Using standard pixel rendering and ray tracing, light emanating fromthis pixel can more or less be considered to emanate from a pointlocated at the geometric center 2310 of the pixel 2300. To implementsubpixel rendering, ray tracing could otherwise be calculated intriplicate by specifically addressing the geometric location of eachsubpixel. Knowing the distribution of subpixels within each pixel,however, calculations can be simplified by maintaining pixel-centeredcomputations and applying appropriate offsets given known geometricsubpixel offsets (i.e. negative horizontal offset 2314 for the redsubpixel 2304, a zero offset for the green 2306 and a positivehorizontal offset 2318 for the blue subpixel 2308). In doing so, lightfield image correction can still benefit from subpixel processingwithout significantly increased computation load.

While this example contemplates a linear (horizontal) subpixeldistribution, other 2D distributions may also be considered withoutdeparting from the general scope and nature of the present disclosure.For example, for a given digital display screen and pixel and subpixeldistribution, different subpixel mappings can be determined to definerespective pixel subcoordinate systems that, when applied to standardpixel-centric ray tracing and image correction algorithms, can allow forsubpixel processing and increase image correction resolution andsharpness without undue processing load increases.

In some embodiments, additional efficiencies may be leveraged on the GPUby storing the image data, for example image 1306, in the GPU's texturememory. Texture memory is cached on chip and in some situations isoperable to provide higher effective bandwidth by reducing memoryrequests to off-chip DRAM. Specifically, texture caches are designed forgraphics applications where memory access patterns exhibit a great dealof spatial locality, which is the case of the steps 1110-1126 of method1100. For example, in method 1100, image 1306 may be stored inside thetexture memory of the GPU, which then greatly improves the retrievalspeed during step 1126 where the color channel associated with theportion of image 1306 at intersection point 1423 is determined.

With reference to FIGS. 24 to 26D, and in accordance with oneembodiment, an exemplary computationally implemented ray-tracing methodfor rendering multiple images or image portions on multiple adjusteddistinct image planes simultaneously via an array of light field shapingelements, or light field shaping layer (LFSL) thereof, will now bedescribed. The previous above-described embodiments were directed tocorrecting a single image by directly or indirectly modifying thelocation of the virtual image plane. In contrast, the below-describedembodiments are directed to a light field display which is generallyoperable to display multiple image planes at different locations/depthssimultaneously. Unlike known stereoscopic effects, the methods as hereindescribed may be implemented to generate varying depth perceptionswithin a same eye, that is, allowing for the monoscopic viewing of aninput to exhibit multiple distinct image perception adjustments (i.e.multiple juxtaposed and/or overlapping depths, enhancements or likeoptical adjustments, compensations, etc.). For example, in someembodiments, distinct image planes may be juxtaposed such that differentsides or quadrants of an image, for example, may be perceived atdifferent depths. In such embodiments, a different effective visioncorrection parameter (e.g. diopter), or depth, may be applied, to eachportion or quadrant. While this approach may result in some distortionsor artefacts at the edges of the areas or quadrants, depending on theimage data to be rendered along these edges, such artefacts may benegligible if at all perceivable. In other embodiments, however,different image portions may be at least partially superimposed suchthat portions at different depths, when viewed from particularperspectives, may indeed appear to overlap. This enables a user to focuson each plane individually, thus creating a 2.5D effect. Thus, a portionof an image may mask or obscure a portion of another image locatedbehind it depending on the location of the user's pupil (e.g. on animage plane perceived to be located at an increased distance from thedisplay than the one of the first image portion). Other effects mayinclude parallax motion between each image plane when the user moves.The following provides a more detailed description of an embodiment inwhich overlapping portions may be addressed via an applicabletransparency parameter resolved by processing each virtual image portionlayer by layer.

Method 2400 of FIG. 24 substantially mirrors method 1100 of FIG. 11, butgeneralizes it to include multiple distinct virtual image planes. Thus,new steps 2406, 2408, and 2435 have been added, while steps 1110 to1122, and 1126 to 1130 are the same as already described above.Meanwhile, when considering a fixed refractor installation, the input ofconstant parameters 1102 may, in such cases, be fixed and integrallydesigned within operation of the device/system.

For example, to account for multiple distinct image planes, image data1306 of input variables 1104 may also include depth information. Thus,any image or image portion may have a respective depth indicator. Thus,at step 2406, a set of multiple virtual image planes may be defined. Onthese planes, images or image portions may be present. Areas aroundthese images may be defined as transparent or see-through, meaning thata user would be able to view through that virtual image plane and see,for example, images or image portions located behind it. At step 2408,any image or image portion on these virtual image planes may beoptionally scaled to fit the display.

As an example, in the previous example of FIGS. 14A-14C, a singlevirtual image plane 1405, showing two circles, was shown. In contrast,FIGS. 26A and 26B show an example wherein each circle is located on itsown image plane (e.g. original virtual plane 1405 with new virtual imageplane 2605). The skilled technician will understand that two planes areshown only as an example and that the method described herein appliesequally well to any number of virtual planes. The only effect of havingmore planes is a larger computational load.

Going back to FIG. 24, steps 1110 to 1122 occur similarly to the onesdescribed in FIG. 11. However, step 1124 has been included and expandedupon in Step 2435, which is described in FIG. 25. In step 2435, aniteration is done over the set of virtual image planes to compute whichimage portion from which virtual image plane is seen by the user. Thus,at step 2505 a virtual image plane is selected, starting from the planelocated closest to the user. Then step 1124 proceeds as describedpreviously for that selected virtual plane. At step 2510 thecorresponding color channel of the intersection point identified at step1124 is sampled. Then at step 2515, a check is made to see if the colorchannel is transparent. If this is not the case, then the sampled colorchannel is sent to step 1126 of FIG. 24, which was already described andwhere the color channel is rendered by the pixel/subpixel. An example ofthis is illustrated in FIGS. 26A and 26B, wherein a user is located sothat a ray vector 2625 computed passing through optical element 2616 andpixel/subpixel 2609 intersects virtual image plane 1405 at location2623. Since this location is non-transparent, this is the color channelthat will be assigned to the pixel/subpixel. However, as this exampleshows, this masks or hides parts of the image located on virtual imageplane 2605. Thus, an example of the image perceived by the user is shownin FIG. 26B.

Going back to FIG. 25, at step 2515 if the color channel is transparent,then another check is made at step 2520 to see if all virtual imageplanes have been iterated upon. If this is the case, then that meansthat no image or image portion is seen by the user and at step 2525, forexample, the color channel is set to black (or any other backgroundcolour), before proceeding to step 1126. If however at least one morevirtual image plane is present, then the method goes back to step 2505and selects that next virtual image plane and repeats steps 1124, 2510and 2515. An example of this is illustrated in FIG. 26C, wherein a useris located so that a distinct ray vector 2675 computed passing throughoptical element 2666 and pixel/subpixel 2659 first intersects atlocation 2673 of virtual image plane 1405. This location is defined tobe transparent, so the method checks for additional virtual image planes(here plane 2605) and computes the intersection point 2693, which isnon-transparent, and thus the corresponding color channel is selected.An example of the image perceived by the user is shown in FIG. 26D.

Going back to FIG. 24, once the pixel/subpixel has been assigned thecorrect color channel at step 1126, the method proceeds as describedpreviously at steps 1128 and 1130.

Similarly, method 2700 of FIG. 27 substantially mirrors method 1900 ofFIG. 19 but also generalizes it to include multiple distinct eye focalplanes, including infinity, as explained above. Thus, in method 2700,steps 1910 to 1921 and 1931 to 1936 are the same as described for method1900. The difference comes from new step 2735 which includes and expandsupon steps 1921 to 1929, as shown in FIG. 28. There, we see that themethod iterates over all designated image planes, starting from theplane corresponding to an image located closest to the user. Thus, a neweye focal plane is selected at step 2805, which is used for steps 1923to 1929 already described above. Once the corresponding image portion islocated at step 1929, at step 2810, the corresponding pixel/subpixelcolor channel is sampled. Then at step 2815, if the color channel isnon-transparent, then the method goes back to step 1931 of FIG. 27,wherein the pixel/subpixel is assigned that color channel. However, ifthe image portion is transparent, then the method iterates to the nextdesignated image plane. Before this is done, the method checks at step2820 if all the eye focal planes have been iterated upon. If this is thecase, then no image portion will be selected and at step 2825 the colorchannel is set to black, for example, before exiting to step 1931. Ifother eye focal planes are still available, then the method goes back tostep 2805 to select the next plane and the method iterates once more.

In some embodiments, methods 2400 or 2700 may be used to implement aphoropter/refractor device to do subjective visual acuity evaluations.For example, as illustrated in FIGS. 29A and 29B, different optotypes(e.g. letters, symbols, etc.) may be displayed simultaneously but atdifferent perceived depths, to simulate the effect of adding arefractive optical component (e.g. change in focus/optical power). InFIG. 29A, two images of the same optotype (e.g. letter E) are displayed,each on their own designated image plane (e.g. here illustrated asvirtual image planes as an example only). In this example, image 2905 islocated on designated image plane 2907 while image 2915 is located ondesignated image plane 2917, which is located further away. In FIG. 29B,we see an example of the perception of both images as perceived by auser with reduced visual acuity (e.g. myopia), for example, wherein theimage closest to the user is seen to be clearer. Thus, a user could bepresented with multiple images (e.g. 2 side-by-side, 4, 6 or 9 in asquare array, etc.) and indicate which image is clearer and/or mostcomfortable to view. An eye prescription may then be derived from thisinformation. Moreover, in general, both spherical and cylindrical powermay be induced by the light field display.

Accordingly, it can be observed that the ray-tracing methods 2400 and2700 noted above, and related light field display solutions, can beequally applied to image perception adjustment solutions for visualmedia consumption, as they can for subjective vision testing solutions,or other technologically related fields of endeavour. As alluded toabove, the light field display and rendering/ray-tracing methodsdiscussed above may all be used to implement, according to variousembodiments, a subjective vision testing device or system such as aphoropter or refractor. Indeed, a light field display may replace, atleast in part, the various refractive optical components usually presentin such a device. Thus, the vision correction light field ray tracingmethods 1100, 1900, 2400, or 2700 discussed above may equally be appliedto render optotypes at different dioptric power or refractive correctionby generating vision correction for hyperopia (far-sightedness) andmyopia (nearsightedness), as was described above in the general case ofa vision correction display. Light field systems and methods describedherein, according to some embodiments, may be applied to create the samecapabilities as a traditional instrument and to open a spectrum of newfeatures, all while improving upon many other operating aspects of thedevice. For example, the digital nature of the light field displayenables continuous changes in dioptric power compared to the discretechange caused by switching or changing a lens or similar; displaying twoor more different dioptric corrections seamlessly at the same time; and,in some embodiments, the possibility of measuring higher-orderaberrations and/or to simulate them for different purposes such as,deciding for free-form lenses, cataract surgery operation protocols, IOLchoice, etc. Such exemplary subjective vision testing and accommodationsystems were previously descried in Applicant's U.S. Pat. No. 10,761,604issued Sep. 1, 2020, the entire disclosure of which is incorporatedherein by reference.

With reference to FIGS. 30, and 31A to 31C, and in accordance withdifferent illustrative, but non-limiting embodiments, an exemplarysubjective vision testing system, generally referred to using thenumeral 3000, will now be described. At the heart of this system is alight field vision testing device such as a light field refractor orphoropter 3001. Generally, the light field phoropter 3001 is a devicecomprising, at least in part, a light field display 3003 and which isoperable to display or generate one or more optotypes to a patienthaving his/her vision acuity (e.g. refractive error) tested. In someembodiments, the light field phoropter may comprise an eye tracker 3009(such as a near-IR camera or other as discussed above) that may be usedto determine the pupil center position in real-time or near real-time,for accurately locating the patient's pupil, as explained above withregard to the ray-tracing methods 1100, 1900, 2400, or 2700. Indeed,FIG. 32 shows a plot of the angular resolution (in arcminutes) of anexemplary light field display comprising a 1500 ppi digital pixeldisplay as a function of the dioptric power of the light field image (indiopters). We clearly see that, in this particular example, the lightfield display is able to generate displacements (line 3205) in dioptersthat have higher resolution corresponding to 20/20 vision (line 3207) orbetter (e.g. 20/15—line 3209) and close to (20/10—line 3211)), herewithin a dioptric power range of 2 to 2.5 diopters. Thus, the lightfield displays and ray-tracing methods described above, according todifferent embodiments, may be used to replace, at least in part,traditional optical components. In some embodiments, a head-rest,eyepiece or similar (not shown) may be used to keep the patient's headstill and in the same location, thus in such examples, foregoing thegeneral utility of a pupil tracker or similar techniques bysubstantially fixing a pupil location relative to this headrest. In someembodiments, phoropter 3001 may comprise a network interface 3023 forcommunicating via network to a remote database or server 3059.

For example, in one embodiment and as illustrated in FIG. 31A, the lightfield phoropter 3001 may comprise light field display 3003 (hereincomprising a MLA 3103 and a digital pixel display 3105) locatedrelatively far away (e.g. one or more meters) from the patient' eyecurrently being diagnosed. Note that the pointed line is used toschematically illustrate the direction of the light rays emitted by thedisplay 3105. Also illustrated is the eye-tracker 3009, which may beprovided as a physically separate element, for example, installed in ata given location in a room or similar. In some embodiments, the notedeye/pupil tracker may include the projection of IR markers/patterns tohelp align the patient's eye with the light field display. In someembodiments, a tolerance window (e.g. “eye box”) may be considered tolimit the need to refresh the ray-tracing iteration. An exemplary valueof the size of the eye box, in some embodiments, is around 6 mm, thoughsmaller (e.g. 4 mm) or larger eye boxes may alternatively be set toimpact image quality, stability or like operational parameters.

Going back to FIG. 30, light field phoropter 3001 may also comprise,according to different embodiments and as will be further discussedbelow, one or more refractive optical components 3007, a processing unit3021, a data storage unit or internal memory 3013, a network interface3023, one or more cameras 3017 and a power module 3023.

In some embodiments, power module 3023 may comprise, for example, arechargeable Li-ion battery or similar. In some embodiments, it maycomprise an additional external power source, such as, for example, aUSB-C external power supply. It may also comprise a visual indicator(screen or display) for communicating the device's power status, forexample whether the device is on/off or recharging.

In some embodiments, internal memory 3013 may be any form of electronicstorage, including a disk drive, optical drive, read-only memory,random-access memory, or flash memory, to name a few examples. In someembodiments, a library of chart patterns (Snellen charts, prescribedoptotypes, forms, patterns, or other) may be located in internal memory3013 and/or retrievable from remote server 3059.

In some embodiments, one or more optical components 3007 can be used incombination with the light field display 3003, for example to shortenthe device's dimensions and still offer an acceptable range in dioptricpower. The general principle is schematically illustrated in the plotsof FIGS. 33A to 33D. In these plots, the image quality (e.g. inverse ofthe angular resolution, higher is better) at which optotypes are smallenough to be useful for vision testing in this plot is above horizontalline 3101 which represents typical 20/20 vision. FIG. 33A shows the plotfor the light field display only, where we see the characteristic twopeaks corresponding to the smallest resolvable point, one of which wasplotted in FIG. 32 (here inverted and shown as a peak instead of abasin), and where each region above the line may cover a few diopters ofdioptric power, according to some embodiments. While the dioptric rangemay, in some embodiments, be more limited than needed when relying onlyon the light field display, it is possible to shift this interval byadding one or more refractive optical components. This is shown in FIG.33B where the regions above the line 3101 is shifted to the left(negative diopters) by adding a single lens in the optical path.

Thus, by using a multiplicity of refractive optical components or byalternating sequentially between different refractive components ofincreasing or decreasing dioptric power, it is possible to shift thecenter of the light field diopter range to any required value, as shownin FIG. 33C, and thus the image quality may be kept above line 3101 forany required dioptric power as shown in FIG. 33D. In some embodiments, arange of 30 diopters from +10 to −20 may be covered for example. In thecase of one or more reels of lenses, the lens may be switched for agiven larger dioptric power increment, and the light field display wouldbe used to provide a finer continuous change to accurately pin-point therequired total dioptric power required to compensate for the patient'sreduced visual acuity. This would still result in light field phoropter3001 having a reduced number of refractive optical components comparedto the number of components needed in a traditional phoropter, whiledrastically enhancing the overall fine-tuning ability of the device.

One example, according to one embodiment, of such a light fieldphoropter 3001 is schematically illustrated in FIG. 31B, wherein thelight field display 3003 (herein shown again comprising MLA 3103 anddigital pixel display 3105) is combined with a multiplicity ofrefractive components 3007 (herein illustrate as a reel of lenses as anexample only). By changing the refractive component used in combinationwith the light field display, a larger dioptric range may be covered.This may also provide means to reduce the device's dimension, making itin some embodiments more portable, and encompass all its internalcomponents into a shell, housing or casing 3111. In some embodiments,the light field phoropter may comprise a durable ABS housing and may beshock and harsh-environment resistant. In some embodiments, the lightfield phoropter 3001 may comprise a telescopic feel for fixed orportable usage; optional mounting brackets, and/or a carrying case. Insome embodiments, all components may be internally protected and sealedfrom the elements.

In some embodiments, the casing may further comprise an eye piece orsimilar that the patient has to look through, which may limit movementof the patient's eye during diagnostic and/or indirectly provide a pupillocation to the light field renderer.

In some embodiments, it may also be possible to further reduce the sizeof the device by adding, for example, a mirror or any device which mayincrease the optical path. This is illustrated in FIG. 31C where thelength of the device was reduced by adding a mirror 3141. This is shownschematically by the pointed arrow which illustrates the light beingemitted from pixel display 3105 travelling through MLA 3103 before beingreflected by mirror 3141 back through refractive components 3007 andultimately hitting the eye.

The skilled technician will understand that different examples ofrefractive components 3007 may include, without limitation, one or morelenses, sometimes arranged in order of increasing dioptric power in oneor more reels of lenses similar to what is typically found intraditional phoropters; an electrically controlled fluid lens; activeFresnel lens; and/or Spatial Light Modulators (SLM). In someembodiments, additional motors and/or actuators may be used to operaterefractive components 3007. These may be communicatively linked toprocessing unit 3021 and power module 3023, and operate seamlessly withlight display 3003 to provide the required dioptric power.

For example, FIGS. 34A and 34B show a perspective view of an exemplarylight field phoropter 3001 similar to the one of FIG. 31B, but whereinthe refractive component 3007 is an electrically tunable liquid lens.Thus, in this particular embodiment, no mechanical or moving componentare used, which may result in the device being more robust. In someembodiments, the electrically tunable lens may have a range of ±13diopters.

In one illustrative embodiment, a 1000 dpi display is used with a MLAhaving a 65 mm focal distance and 1000 μm pitch with the user's eyelocated at a distance of about 26 cm. A similar embodiment uses the sameMLA and user distance with a 3000 dpi display.

Other displays having resolutions including 750 dpi, 1000 dpi, 1500 dpiand 3000 dpi were also tested or used, as were MLAs with a focaldistance and pitch of 65 mm and 1000 43 mm and 525 μm, 65 mm and 590 μm,60 mm and 425 μm, 30 mm and 220 μm, and 60 mm and 425 μm, respectively,and user distances of 26 cm, 45 cm or 65 cm.

Going back to FIG. 30, in some embodiments, eye-tracker 3009 may be adigital camera, in which case it may be used to further acquire imagesof the patient's eye to provide further diagnostics, such as pupillaryreflexes and responses during testing for example. In other embodiments,one or more additional cameras 3017 may be used to acquire these imagesinstead. In some embodiments, light field phoropter 3001 may comprisebuilt-in stereoscopic tracking cameras.

In some embodiments, feedback and/or control of the vision test beingadministered may be given via a control interface 3011. In someembodiments, the control interface 3011 may comprise a dedicatedhandheld controller-like device 3045. This controller 3045 may beconnected via a cable or wirelessly, and may be used by the patientdirectly and/or by an operator like an eye professional. In someembodiments, both the patient and operator may have their own dedicatedcontroller. In some embodiments, the controller may comprise digitalbuttons, analog thumbstick, dials, touch screens, and/or triggers.

In some embodiments, control interface 3011 may comprise a digitalscreen or touch screen, either on the phoropter device itself or on anexternal module. In other embodiments, the control interface may letother remote devices control the light field phoropter via the networkinterface. For example, remote digital device 3043 may be connected tolight field phoropter by a cable (e.g. USB cable, etc.) or wirelessly(e.g. via Bluetooth or similar) and interface with the light fieldphoropter via a dedicated application, software or website. Such adedicated application may comprise a graphical user interface (GUI), andmay also be communicatively linked to remote database 3059.

In some embodiments, the patient may give feedback verbally and theoperator may control the vision test as a function of that verbalfeedback. In some embodiments, phoropter 3001 may comprise a microphoneto record the patient's verbal communications, either to communicatethem to a remote operator via network interface 3023 or to directlyinteract with the device (e.g. via speech recognition or similar).

In some embodiments, processing unit 3021 may be communicativelyconnected to data storage 3013, eye tracker 3009, light field display3003 and refractive components 3007. Processing unit 3021 may beresponsible for rendering one or more optotypes via light field display3003 and, in some embodiments, jointly control refractive components3007 to achieve a required total dioptric power. It may also be operableto send and receive data to internal memory 3013 or to/from remotedatabase 3059.

In some embodiments, diagnostic data may be automaticallytransmitted/communicated to remote database 3059 or remote digitaldevice 3043 via network interface 3023 through the use of a wired orwireless network connection. The skilled artisan will understand thatdifferent means of connecting electronic devices may be consideredherein, such as, but not limited to, Wi-Fi, Bluetooth, NFC, Cellular,2G, 3G, 4G, 5G or similar. In some embodiments, the connection may bemade via a connector cable (e.g. USB including microUSB, USB-C,Lightning connector, etc.). In some embodiments, remote digital device3043 may be located in a different room, building or city.

In some embodiments, two light field phoropters 3001 may be combinedside-by-side to independently measure the visual acuity of both left andright eye at the same time. An example is shown in FIG. 35, where twounits corresponding to the embodiment of FIGS. 34A and 34B (used as anexample only) are placed side-by-side or fused into a single device.

In some embodiments, a dedicated application, software or website mayprovide integration with third party patient data software. In someembodiments, the phoropter's software may be updated on-the-fly via anetwork connection and/or be integrated with the patient's smartphoneapp for updates and reminders.

In some embodiments, the dedicated application, software or website mayfurther provide a remote, real-time collaboration platform between theeye professional and patient, and/or between different eyeprofessionals. This may include interaction between differentparticipants via video chat, audio chat, text messages, etc.

In some embodiments, light field phoropter 3001 may be self-operated oroperated by an optometrist, ophthalmologist or other certified eye-careprofessional. For example, in some embodiments, a patient could usephoropter 3001 in the comfort of his/her own home.

With reference to FIG. 36 and in accordance with different exemplaryembodiments, a dynamic subjective vision testing method using visiontesting system 3000, generally referred to using the numeral 3600, willnow be described. As mentioned above, the use of a light field displayenables phoropter 3001 of vision testing system 3000 to provide moredynamic and/or more modular vision tests than what is generally possiblewith traditional phoropters. Generally, method 3600 seeks to diagnose apatient's reduced visual acuity and produce therefrom, in someembodiments, an eye prescription or similar.

In some embodiments, eye prescription information may include, for eacheye, one or more of: distant spherical, cylindrical and/or axis values,and/or a near (spherical) addition value.

In some embodiments, the eye prescription information may also includethe date of the eye exam and the name of the eye professional thatperformed the eye exam. In some embodiments, the eye prescriptioninformation may also comprise a set of vision correction parameter(s)201 used to operate any vision correction light field displays using thesystems and methods described above. In some embodiments, the eyeprescription may be tied to a patient profile or similar, which maycontain additional patient information such as a name, address orsimilar. The patient profile may also contain additional medicalinformation about the user. All information or data (i.e. set of visioncorrection parameter(s) 201, user profile data, etc.) may be kept onremote database 3059. Similarly, in some embodiments, the user's currentvision correction parameter(s) may be actively stored and accessed fromexternal database 3059 operated within the context of a server-basedvision correction subscription system or the like, and/or unlocked forlocal access via the client application post user authentication withthe server-based system.

Phoropter 3001 being, in some embodiments, portable, a large range ofenvironment may be chosen to deliver the vision test (home, eyepractitioner's office, etc.). At the start, the patient's eye may beplaced at the required location. This is usually by placing his/her headon a headrest or by placing the objective (eyepiece) on the eye to bediagnosed. As mentioned above, the vision test may be self-administeredor partially self-administered by the patient. For example, the operator(e.g. eye professional or other) may have control over the type of testbeing delivered, and/or be the person who generates or helps generatetherefrom an eye prescription, while the patient may enter inputsdynamically during the test (e.g. by choosing or selecting an optotype,etc.).

As discussed above, the light field rendering method 3600 generallyrequires an accurate location of the patient's pupil center. Thus, atstep 3605, such a location is acquired. In some embodiments, such apupil location may be acquired via eye tracker 3009, either once, atintervals, or continuously. In other embodiments, the location may bederived from the device or system's dimension. For example, in someembodiments, the use an eye-piece or similar provides an indirect meansof deriving the pupil location. In some embodiments, the phoropter 3001may be self-calibrating and not require any additional externalconfiguration or manipulation from the patient or the practitionerbefore being operable to start a vision test.

At step 3610, one or more optotypes is/are displayed to the patient, atone or more dioptric power (e.g. in sequence, side-by-side, or in a gridpattern/layout). The use of light field display 3003 offers multiplepossibilities regarding how the optotypes are presented, and at whichdioptric power each may be rendered. The optotypes may be presentedsequentially at different dioptric power, via one or more dioptric powerincrements. In some embodiments, the patient and/or operator may controlthe speed and size of the dioptric power increments.

In some embodiments, optotypes may also be presented, at least in part,simultaneously on the same image but rendered at a different dioptricpower (via ray-tracing methods 2400, or 2700, for example). For example,FIG. 37 shows an example of how different optotypes may be displayed tothe patient but rendered with different dioptric power simultaneously.These may be arranged in columns or in a table or similar. In FIG. 37,we see two columns of three optotypes (K, S, V), varying in size, asthey are perceived by a patient, each column being rendered at differentdegrees of refractive correction (e.g. dioptric power). In this specificexample, the optotypes on the right are being perceived as blurrier thanthe optotypes on the left.

Thus, at step 3615, the patient would communicate/verbalize thisinformation to the operator or input/select via control interface 3011the left column as the one being clearer. Thus, in some embodiments,method 3600 may be configured to implement dynamic testing functionsthat dynamically adjust one or more displayed optotype's dioptric powerin real-time in response to a designated input, herein shown by thearrow going back from step 3620 to step 3610. In the case ofsequentially presented optotypes, the patient may indicate when theoptotypes shown are clearer. In some embodiments, the patient maycontrol the sequence of optotypes shown (going back and forth as neededin dioptric power), and the speed and increment at which these arepresented, until he/she identifies the clearest optotype. In someembodiments, the patient may indicate which optotype or which group ofoptotypes is the clearest by moving an indicator icon or similar withinthe displayed image.

In some embodiments, the optotypes may be presented via a video feed orsimilar.

In some embodiments, when using a reel of lenses or similar,discontinuous changes in dioptric power may be unavoidable. For example,the reel of lenses may be used to provide a larger increment in dioptricpower, as discussed above. Thus, step 3610 may in this case comprisefirst displaying larger increments of dioptric power by changing lens asneeded, and when the clearest or less blurry optotypes are identified,fine-tuning with continuous or smaller increments in dioptric powerusing the light field display. In the case of optotypes presentedsimultaneously, the refractive components 3007 may act on all optotypesat the same time, and the change in dioptric power between them may becontrolled only by the light display 3003. In some embodiments, forexample when using an electrically tunable fluid lens or similar, thechange in dioptric power may be continuous.

In some embodiments, eye images may be recorded during steps 3610 to3620 and analyzed to provide further diagnostics. For example, eyeimages may be compared to a bank or database of proprietary eye examimages and analyzed, for example via an artificial intelligence (AI) orMachine-learning (ML) system or similar. This analysis may be done byphoropter 3001 locally or via a remote server or database 3059.

Once the correct dioptric power needed to correct for the patient'sreduced visual acuity is defined at step 3625, an eye prescription orvision correction parameter(s) may be derived from the total dioptricpower used to display the best perceived optotypes.

In some embodiments, the patient, an optometrist or other eye-careprofessional may be able to transfer the patient's eye prescriptiondirectly and securely to his/her user profile store on said server ordatabase 3059. This may be done via a secure website, for example, sothat the new prescription information is automatically uploaded to thesecure user profile on remote database 3059. In some embodiments, theeye prescription may be sent remotely to a lens specialist or similar tohave prescription glasses prepared.

In some embodiments, the vision testing system 3000 may also oralternatively be used to simulate compensation for higher-orderaberrations. Indeed, the light field rendering methods 1100, 1900, 2400,or 2700 described above may be used to compensation for higher orderaberrations (HOA), and thus be used to validate externally measured ortested HOA via method 3600, in that a measured, estimated or predictedHOA can be dynamically compensated for using the system described hereinand thus subjectively visually validated by the viewer in confirmingwhether the applied HOA correction satisfactory addresses otherwiseexperienced vision deficiencies. In one such embodiment, a HOAcorrection preview can be rendered, for example, in enabling users toappreciate the impact HOA correction (e.g. HOA compensating eyewear orcontact lenses, intraocular lenses (IOL), surgical procedures, etc.), ordifferent levels or precisions thereof, could have on their visualacuity. Alternatively, HOA corrections once validated can be applied ondemand to provide enhanced vision correction capabilities to consumerdisplays.

Higher-order aberrations can be defined in terms of Zernike polynomials,and their associated coefficients. In some embodiments, the light fieldphoropter may be operable to help validate or confirm measuredhigher-order aberrations, or again to provide a preview of how certainHOA corrections may lead to different degrees of improved vision. To doso, in some embodiments, the ray-tracing methods 1100, 1900, 2400, or2700 may be modified to account for the wavefront distortion causing theHOA which are characterized by a given set of values of the Zernikecoefficients. Such an approach may include, in some embodiments,extracting or deriving a set of light rays corresponding to a givenwavefront geometry. Thus, the light field display may be operable tocompensate for the distortion by generating an image corresponding to an“opposite” wavefront aberration. In some embodiments, the correspondingtotal aberration values may be normalized for a given pupil size ofcircular shape. Moreover, in some embodiments, the wavefront may bescaled, rotated and transformed to account for the size and shape of theview zones. This may include concentric scaling, translation of pupilcenter, and rotation of the pupil, for example.

While the present disclosure describes various embodiments forillustrative purposes, such description is not intended to be limited tosuch embodiments. On the contrary, the applicant's teachings describedand illustrated herein encompass various alternatives, modifications,and equivalents, without departing from the embodiments, the generalscope of which is defined in the appended claims. Except to the extentnecessary or inherent in the processes themselves, no particular orderto steps or stages of methods or processes described in this disclosureis intended or implied. In many cases the order of process steps may bevaried without changing the purpose, effect, or import of the methodsdescribed.

Information as herein shown and described in detail is fully capable ofattaining the above-described object of the present disclosure, thepresently preferred embodiment of the present disclosure, and is, thus,representative of the subject matter which is broadly contemplated bythe present disclosure. The scope of the present disclosure fullyencompasses other embodiments which may become apparent to those skilledin the art, and is to be limited, accordingly, by nothing other than theappended claims, wherein any reference to an element being made in thesingular is not intended to mean “one and only one” unless explicitly sostated, but rather “one or more.” All structural and functionalequivalents to the elements of the above-described preferred embodimentand additional embodiments as regarded by those of ordinary skill in theart are hereby expressly incorporated by reference and are intended tobe encompassed by the present claims. Moreover, no requirement existsfor a system or method to address each and every problem sought to beresolved by the present disclosure, for such to be encompassed by thepresent claims. Furthermore, no element, component, or method step inthe present disclosure is intended to be dedicated to the publicregardless of whether the element, component, or method step isexplicitly recited in the claims. However, that various changes andmodifications in form, material, work-piece, and fabrication materialdetail may be made, without departing from the spirit and scope of thepresent disclosure, as set forth in the appended claims, as may beapparent to those of ordinary skill in the art, are also encompassed bythe disclosure.

While the present disclosure describes various exemplary embodiments,the disclosure is not so limited. To the contrary, the disclosure isintended to cover various modifications and equivalent arrangementsincluded within the general scope of the present disclosure.

What is claimed is:
 1. A computer-implemented method, automaticallyimplemented by one or more digital processors, to adjust user perceptionof an image portion to be rendered via a set of pixels and acorresponding array of light field shaping elements (LFSE), the methodcomprising, for each given pixel of at least some of the set of pixels,digitally: projecting an adjusted image ray trace between said givenpixel and a user pupil location to intersect an adjusted image locationfor a given perceived image depth given a direction of a light fieldemanated by said given pixel based on a given LFSE intersected thereby;upon said adjusted image ray trace intersecting a given image portionassociated with said given perceived image depth, associating with saidgiven pixel an adjusted image portion value designated for said adjustedimage location based on said intersection; and rendering for each saidgiven pixel said adjusted image portion value associated therewith,thereby perceptively rendering said adjusted image portion at saidperceived image depth.
 2. The computer-implemented method of claim 1, toadjust perception of distinct image portions, further comprising, uponsaid adjusted image ray trace failing to intersect said given imageportion associated with said given perceived image depth, repeating saidprojecting and associating for a subsequent perceived image depth andadjusted image portion associated therewith, thereby renderingdistinctly perceptively adjusted image portions perceptively rendered atrespectively corresponding perceived image depths.
 3. Thecomputer-implemented method of claim 2, wherein each of said imageportions is digitally mapped to a corresponding virtual image planevirtually positioned relative to the pixels at said respectivelycorresponding perceived image depths, and wherein said intersection isdefined on said corresponding virtual image plane.
 4. Thecomputer-implemented method of claim 2, wherein each of said imageportions is mapped to a user retinal plane in accordance with said givenperceived image depth based on a user eye focus parameter, and whereinsaid intersection is defined on said retinal plane by redirecting saidadjusted image ray trace at said pupil location in accordance with saiduser eye focus parameter.
 5. The computer-implemented method of claim 1,wherein said projecting and associating are implemented in parallel foreach said given pixel of at least a subset of said pixels.
 6. Thecomputer-implemented method of claim 2, wherein said distinct imageportions are to be perceptively rendered side-by-side at saidrespectively corresponding perceived image depths.
 7. Thecomputer-implemented method of claim 6, wherein said distinct imageportions are to be perceptively rendered side-by-side at saidrespectively corresponding perceived image depths in a 2-dimentionalgrid or in respective image quadrants.
 8. The computer-implementedmethod of claim 6, wherein each of said image portions correspond to anoptotype simultaneously rendered in each of said portions side-by-sideat distinct perceived image depths to subjectively assess a user'sreduced visual acuity.
 9. The computer-implemented method of claim 2,wherein overlap between said image portions are automatically addressedby rendering a nearest perceptive depth.
 10. The computer-implementedmethod of claim 8, wherein each of said respectively correspondingperceived image depths are dynamically varied so to subjectively assessthe user's reduced visual acuity.
 11. The computer-implemented method ofclaim 1, further comprising, prior to said projecting: calculating avector between said given pixel and said user pupil location; andapproximating said direction of said light field emanated by said givenpixel based on said given LFSE intersected by said vector.
 12. Anon-transitory computer-readable medium comprising digital instructionsto be implemented by one or more digital processors to automaticallyadjust user perception of distinct image portions to be rendered on adigital display via a set of pixels thereof and an array of light fieldshaping elements (LFSE) disposed relative thereto, by, for each givenpixel of at least some of the set of pixels, digitally: digitallyprojecting an adjusted image ray trace between said given pixel and auser pupil location to intersect an adjusted image location for a givenperceived image depth given a direction of a light field emanated bysaid given pixel based on a given LFESE intersected thereby; upon saidadjusted image ray trace intersecting a given image portion associatedwith said given perceived image depth, associating with said given pixelan adjusted image portion value designated for said adjusted imagelocation based on said intersection to be rendered accordingly; andotherwise repeating said projecting and associating for a subsequentperceived image depth and adjusted image portion associated therewith;thereby rendering distinctly perceptively adjusted image portionsperceptively rendered at respectively corresponding perceived imagedepths.
 13. The computer-readable medium of claim 12, further comprisinginstructions for: calculating a vector between said given pixel and saiduser pupil location; and approximating said direction of said lightfield emanated by said given pixel based on said given LFSE intersectedby said vector.
 14. The computer-readable medium of claim 12, whereineach of said image portions is digitally mapped to a correspondingvirtual image plane virtually positioned relative to the digital displayat said respectively corresponding perceived image depths, and whereinsaid intersection is defined on said corresponding virtual image plane.15. The computer-readable medium of claim 12, wherein each of said imageportions is mapped to a user retinal plane in accordance with said givenperceived image depth based on a user eye focus parameter, and whereinsaid intersection is defined on said retinal plane by redirecting saidadjusted image ray trace at said pupil location in accordance with saiduser eye focus parameter.
 16. The computer-readable medium of claim 12,wherein said distinct image portions are to be perceptively renderedside-by-side at said respectively corresponding perceived image depths.17. The computer-readable medium of claim 16, wherein each of said imageportions correspond to an optotype simultaneously rendered in each ofsaid portions side-by-side at distinct perceived image depths tosubjectively assess a user's reduced visual acuity.
 18. Thecomputer-readable medium of claim 12, wherein overlap between said imageportions are automatically addressed by rendering a nearest perceptivedepth.